I am not happy with Radar Contact, I have been waiting for their upgrade for years but probably will never come. After I switched to FSX from FS9, RC became buggy, probably RC was never designed for FSX. Anyone knows of similar payware out there that does the same job as RC?
I don't think there is anything other than Radar Contact that is payware.
You'll either have to use Default ATC or fly on VATSIM.
You are probably looking for VOX-ATC, an excellent product. I have never used Radar Contact but according to the VOX-ATC forum, those that have, like VOX-ATC better.