A Bit Of Advice

I need to quit the telemarketing dance gig. How do I do it?

Here is some background:

I started working for this ballroom company back in 2007. It was a lot of fun but ultimately doomed for me since I was supposed to sell, sell, sell and all I really wanted to do was to dance and teach. In any event, the manager was pretty great (although she could be a passive aggressive bitch sometimes) and I left on good terms. A couple of years later, I was asked to come back to teach ballroom to kids in schools. I happily agreed and LOVED IT (still do!). Then, when the studio hired a new marketing director, they needed someone to make the marketing calls that she drummed up. They asked me and I agreed. But I guess I didn't read the fine print. At first I just called back the people who had inquired about the dance school. That only lasted a week. What they really wanted me to do was make cold calls. Cold calls are where I call up random people from the phone book and try to get them to come in and take dance classes. Yeah...no. On the first day, I was hung up on, cursed out, and I called someone who had only one leg. Not fun. This really is not my thing, no matter how much they pay me (about $200/wk for 15 hours of work).

Today, I have a final so I was able to get out of working, but it is my intent to NEVER go back. How can I extricate myself from this job (right away) without ruining my relationship with the owners? I would like to keep teaching kids, but I don't really want to do much work in the studio. Should I try to find someone to take my place? Should I keep giving excuses? Or should I just tell them the truth: that I really don't think that the job is for me?

Any advice?