I'll try and be a bit more helpful than the last post 
The safest way to back up your contacts is to have them linked to a google account.
I find it also helps because I can check my e-mails, and update my contacts on my PC rather than on the phone, same with google calender.
Hopefully you had them linked, then it's just a case of logging back in and re-syncing. They should all then re-appear.
If not, then maybe your loss is someone elses gain, somebody reading this thread will realise they've not backed up their contacts and need to do it :smileygrin:
In my view, if you would like to recover deleted Sony phone contacts directly. You can use some android tools. To choose a professional tool is very important for us. Because we can more easily solve our problems, The professional tools capable of handling more specialized. 
