My iphone 4 deleted contacts

Do you close open apps? Double click the home button and a small bar will come up on the bottom, you should delete everything in that bar. Your phone might have been running too much at one time and that may be why it happened. Your information should automatically be backed up on your computer's itunes or icloud though.

To restore a deleted contact on your iPhone, all you do is:
Step #1. Connect your iPhone to the PC/Mac.
Step #2. Open iTunes.
Step #3. Click on Devices tab.
Step #4. Right-click on the iPhone that's connected and click 'Restore from Backup...'
Step #5. Note that this will effectively remove all old information on your iPhone and get the backup data on your iPhone. If you had backed up contacts too in your previous iTunes backup, those will be restored to the iPhone and you should mostly recover that deleted contact now.
And for more details you can look this app known as Whatsapp Recovery for iPhone that will help you a lot for recovering your Data that was deleted.

This used to happen a lot on my wife's iPhone 4s,
within a day or so they would just reappear, try rebooting a
couple of times a day. Failing that check your backup settings on your phone - if you have selected the cloud option then your ok to
use that backup to recover your contacts.

Since you don't have any backup of your iPhone contacts, the only way to get them back is to use a 3rd party iPhone Contact Recovery program. Here I'll show you how to recover deleted contacts from iPhone 4 without backup.

1. Scan your iPhone. Connect your iPhone to computer. As entering the main interface of iPhone Contact Recovery, you will see 2 scanning mode - "Recover from iOS Device" and "Recover from iTunes Backup". Just choose the former one and click "Start" button, then the program will give a deep scanning for your iPhone.

2. Preview and Choose iPhone Contacts. The iPhone contact recovery software will finish the scanning within few minutes. Then you will see all your iPhone data are listed in different categories on program left side. Just go to "Contacts" category, preview all founded contacts and tick the ones you need for recovery. Note that you can preview the deleted contacts only by clicking the check-box "Only display the deleted items" on the left corner of the interface.

3. Restore iPhone Contacts. After selection, just click "Recover" button on the bottom right and the program will lead you to set a saving folder for your output contacts. Then click "Go" button to start to recover iPhone contacts without backup.
http://www.leawo.org/tutorial/how-to-recover-deleted-contacts-from-iphone-without-backup.html

Firstly, do nothing to this iPhone and plunge it to computer to see whether your phone memory card is still readable.
You can find your missing contacts stored on your phone card?
If not, download phone memory card data recovery software to rescue your needed contacts back with ease:
http://freeware-fix.blogspot.com/2013/03/memory-card-recovery.html
Its four data recovery mode would thoroughly scan your phone card and do its utmost to rescue your wanted stuffs back.
Note: Make data backups well.

For the purpose of keep your privacy safe, you'd better do something before you change or sell your old iPhone. Deleting all data on your iPhone completely and permanently is a best choice to prevent your important private data from leaking.
To Move Contacts group from iPhone Permanently,you must to use a iPhone data eraser software.This use guide about how to Wipe iPhone contacts permanently,it can help you delete all contacts from iPhone permanently.
How to Delete Contacts on iPhone
iPhone Data Eraser Clean up Data Safeguard for Ultimate Privacy...