Retrieve all contacts phone numbers in iOS

Try this it works for iOS 6 as well as iOS 5.0 or older:

Sample Project Demo

First add the following frameworks in Link Binary With Libraries

• AddressBookUI.framework
• AddressBook.framework

Then Import

#import <AddressBook/ABAddressBook.h>
#import <AddressBookUI/AddressBookUI.h>

Then use the following code

Requesting permission to access address book

ABAddressBookRef addressBook = ABAddressBookCreateWithOptions(NULL, NULL);

__block BOOL accessGranted = NO;

if (&ABAddressBookRequestAccessWithCompletion != NULL) { // We are on iOS 6
    dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);

    ABAddressBookRequestAccessWithCompletion(addressBook, ^(bool granted, CFErrorRef error) {
        accessGranted = granted;
        dispatch_semaphore_signal(semaphore);
    });

    dispatch_semaphore_wait(semaphore, DISPATCH_TIME_FOREVER);
    dispatch_release(semaphore);
}

else { // We are on iOS 5 or Older
    accessGranted = YES;
    [self getContactsWithAddressBook:addressBook];
}

if (accessGranted) {
    [self getContactsWithAddressBook:addressBook];
}

Retrieving contacts from addressbook

// Get the contacts.
- (void)getContactsWithAddressBook:(ABAddressBookRef )addressBook {

    contactList = [[NSMutableArray alloc] init];
    CFArrayRef allPeople = ABAddressBookCopyArrayOfAllPeople(addressBook);
    CFIndex nPeople = ABAddressBookGetPersonCount(addressBook);

    for (int i=0;i < nPeople;i++) {
        NSMutableDictionary *dOfPerson=[NSMutableDictionary dictionary];

        ABRecordRef ref = CFArrayGetValueAtIndex(allPeople,i);

        //For username and surname
        ABMultiValueRef phones =(__bridge ABMultiValueRef)((__bridge NSString*)ABRecordCopyValue(ref, kABPersonPhoneProperty));

        CFStringRef firstName, lastName;
        firstName = ABRecordCopyValue(ref, kABPersonFirstNameProperty);
        lastName  = ABRecordCopyValue(ref, kABPersonLastNameProperty);
        [dOfPerson setObject:[NSString stringWithFormat:@"%@ %@", firstName, lastName] forKey:@"name"];

        //For Email ids
        ABMutableMultiValueRef eMail  = ABRecordCopyValue(ref, kABPersonEmailProperty);
        if(ABMultiValueGetCount(eMail) > 0) {
            [dOfPerson setObject:(__bridge NSString *)ABMultiValueCopyValueAtIndex(eMail, 0) forKey:@"email"];

        }

        //For Phone number
        NSString* mobileLabel;

        for(CFIndex j = 0; j < ABMultiValueGetCount(phones); j++) {
            mobileLabel = (__bridge NSString*)ABMultiValueCopyLabelAtIndex(phones, j);
            if([mobileLabel isEqualToString:(NSString *)kABPersonPhoneMobileLabel])
            {
                [dOfPerson setObject:(__bridge NSString*)ABMultiValueCopyValueAtIndex(phones, j) forKey:@"phone"];
            }
            else if ([mobileLabel isEqualToString:(NSString*)kABPersonPhoneIPhoneLabel])
            {
                [dOfPerson setObject:(__bridge NSString*)ABMultiValueCopyValueAtIndex(phones, j) forKey:@"phone"];
                break ;
            }

        }
    [contactList addObject:dOfPerson];

    }
NSLog(@"Contacts = %@",contactList);
}

To retrive other information

// All Personal Information Properties
kABPersonFirstNameProperty;          // First name - kABStringPropertyType
kABPersonLastNameProperty;           // Last name - kABStringPropertyType
kABPersonMiddleNameProperty;         // Middle name - kABStringPropertyType
kABPersonPrefixProperty;             // Prefix ("Sir" "Duke" "General") - kABStringPropertyType
kABPersonSuffixProperty;             // Suffix ("Jr." "Sr." "III") - kABStringPropertyType
kABPersonNicknameProperty;           // Nickname - kABStringPropertyType
kABPersonFirstNamePhoneticProperty;  // First name Phonetic - kABStringPropertyType
kABPersonLastNamePhoneticProperty;   // Last name Phonetic - kABStringPropertyType
kABPersonMiddleNamePhoneticProperty; // Middle name Phonetic - kABStringPropertyType
kABPersonOrganizationProperty;       // Company name - kABStringPropertyType
kABPersonJobTitleProperty;           // Job Title - kABStringPropertyType
kABPersonDepartmentProperty;         // Department name - kABStringPropertyType
kABPersonEmailProperty;              // Email(s) - kABMultiStringPropertyType
kABPersonBirthdayProperty;           // Birthday associated with this person - kABDateTimePropertyType
kABPersonNoteProperty;               // Note - kABStringPropertyType
kABPersonCreationDateProperty;       // Creation Date (when first saved)
kABPersonModificationDateProperty;   // Last saved date

// All Address Information Properties
kABPersonAddressProperty;            // Street address - kABMultiDictionaryPropertyType
kABPersonAddressStreetKey;
kABPersonAddressCityKey;
kABPersonAddressStateKey;
kABPersonAddressZIPKey;
kABPersonAddressCountryKey;
kABPersonAddressCountryCodeKey;

Further Reference Read Apple Docs

UPDATE:
You need to add description about why you need to access the contacts in you Apps-Info.plist

Privacy - Contacts Usage Description

OR

<key>NSContactsUsageDescription</key>
<string>Write the reason why your app needs the contact.</string>

For getting the user image.

UIImage *contactImage;
if(ABPersonHasImageData(ref)){
 contactImage = [UIImage imageWithData:(__bridge NSData *)ABPersonCopyImageData(ref)];
}

NOTE:

The AddressBook framework is deprecated in iOS 9 and replaced with the new and improved Contacts Framework