Call breaks for 1 second after 5secs

When I call someone or if I receive a call it makes no difference. After 5 seconds, call brakes, I can't hear anything for one second, and after that everything is back to normal. EVERY time same thing. I tried stock rom, stock rom not from my provider, slim bean, MIUI...same thing :( Factory, no help, remove sim, reset, remove battery..no help. Tried my sim card in different phone, works fine.

I don't know what to do except to return it for repair. Any help is welcome.

Thank you!