sundance-communications.com Forums General General Telephone & Systems Information dialing through a secondary carrier- weird set up

So, I have a customer that is having problems with their carrier. When they make local calls it hands off between carriers and we think they are fighting. My customer asked if there is a some sort of service, even for a fee, where you can call, say an 800#, enter a code, then dial the number you use to. Perhaps kind of like the old calling card situation. Any ideas? TIA