Info contacts deleted

Hellow, few days ago my iphone 6 with ios 8.2 started to delete the info of some contacts and when i try to save a new one a few minutes after its like if i had not saved it.Yesterday i restored the iphone and while restoring i had 2813 contacts. when it finished restoring now i have 2547 contacts. Is there any limit of number of contacts i can save? The iphone has 64gb of memory.

What happens??

Thank you for your help.