Restore from backup iPhone 4s?

I backed up my iPhone n then done a factory reset at the store. Now when I restore from backup no contacts, photos messages being restored? Why?

Seems you've done a partial backup or the Back up was corrupted in the process. Your best bet is to just add the contacts back, at least you didn't lose other data.

You need to check what your backing up by going to iCloud on your phone settings and make sure everything you want to back up is on

Once you restore your phone to factory settings, you may end up
losing some of your data. It is vital that you back up your data before you restore your phone to factory settings. If you forgot to backup, so you can try iTunes data recovery program( here is the one most people recommend: https://www.any-data-recovery.com/product/itunes-data-recovery.htm ) to restore iPhone 4s from backup