What brand of radio is it?? That will determine where you send it.

But that advice is spot on correct. If a plane has been involved in a crash you should consider all of the onboard components suspect (yes, even the servos) and should be checked before reuse. Unless you know for a fact what caused the crash (like dumb thumbs), and it wasn't the switch, then you should throw away the switch. In your case where you lost complete radio functions the switch is certainly suspect and should be replaced. Trust me, it's cheap insurance. Receivers should never be used after a crash until they have been check by a service center. Make sure that you tell them it was involved in a crash so they know to inspect the circuit board. Putting a receiver back in a plane after a crash is just begging to lose another plane. I've seen this happen too many times with other pilots, and all I can do is shake my head and wonder why they are being so dumb. Servos usually don't need to be sent in for service, but do need to be inspected before reuse. Crashes can damage gear trains which can result in lose of function when put back in use. Most brands of servos make gear replacements for their servos, so you can rebuild/repair them yourself.

Thoughts listed above about flying out of range are more than likely not likely. They rule of thumb for our radios is that you can control them farther away than you can see. These radios have a range of about a mile to a mile and a half. Trust me, at a mile away you wouldn't be able to see the plane any longer. So I wouldn't worry about that.

Hope this helps

Ken