ERROR 15 on steam

hey,i bought a game a few hours ago and i have a ‘‘error 15 steam servers are busy’’ anyone know how to fix this ?

If they are busy, you just should wait till they get a bit free.
But I think you have to only relogin to Steam or relaunch Steam, or just reboot your PC

i try relogin, relaunch and reboot my pc and nothing happened

Basically that means that your copy of the game won’t work at your place.
You should do a refund and buy a proper version that is intended for your region.

Also if you bought a game from not an official store (or a physical disk that was made outside your country) that also can be the problem and prevent you from a refund. You should deal with that store yourself in this case.
I believe you couldn’t buy a wrong version from Steam, the official game store.
If you buy the game officially from Steam you shoudn’t face with this problem