iphone 7 no service

Two more suggestions:

Have you already tried all the steps provided in this support guide?:--> If you see No Service or Searching on your iPhone or iPad - Apple Support

Have you tried to contact an Apple reseller or authorized repairer in Greece or Turkey and ask them what are your options? See these pages: For Greece--> https://locate.apple.com/gr/en

For Turkey--> https://locate.apple.com/tr/en

Regards

Giulio

Check if your 7 is eligible for this repair program:--> iPhone 7 Repair Program for "No Service" Issues - Apple Support

Regards

Giulio

Sorry about that.

Have you tried to click on the "contact Apple" or "Apple Technical Support", written in blue in the article I posted in my previous reply?

Regards

Giulio