Why do the name servers on my domain name keep defaulting to the your server?
Your DNS would only revert to ours if you used some type of our mail forwarding features, url forwarding/framing, cnames, address forwarding, and mx forwarding after settings your name up to correctly use your own DNS. Once you use your own DNS you must make these changes with your web host and not our as this will cause your name/s to use our dns again.