Not receiving call unless its telkom since porting to telkom prepaid!

I recently ported a MTN prepaid number to a Telkom prepaid, now i cant receive any calls unless it is from a telkom number, it goes straight to voicemail where it is the voicemail i have missed so many work related calls from clients which is unexceptable. I have phoned telkom contact center support, and the store i bought it from Cresta mall and i have not received an answer, the service through out getting this new telkom poor to say the least took the whole to port the had to go to Mapony mall with help went back Cresta mall, but wont go into the detail on that as i just want my phone/simcard functioning as it should.