Exclamation Unable to answer calls [resolved]

I have been using my HTC Salsa for over a month now without any problems but lately I'm unable to answer calls nor able to receive calls. I have to restart the phone then I can make/recieve one or two calls max, then the same problem resumes. This is very annoying. Has anyone faced a similar issue? What can I do to resolve my problem. t.i.a

I have not installed any new software or updates lately.