Sounds like you have a phone that was jailbroken or hacked to unlock it. Updating it has permanently bricked it if that's the case.
If it wasn't jailbroken or hacked, then the "shop" you took it too broke it. Apple does not repair iPhones, they replace them entirely, so you could not have had it serviced at an Apple approved facility.
Your only option is to take it back to the place that broke it, or find a competent repair shop.