Can anyone tell me how to get iTunes to stop trying to downloading this T.V. program?

I made the mistake of purchasing the high definition version of a television program I wanted to watch. I’ve made my peace with paying the $2.99 for my mistake but the big problem is that the HD version takes so long to download. I don’t use iTunes all that much but I have deleted, cancelled, stopped that damn thing everywhere and every way I can think of and know how to do, I’ve done everything I know how to get rid of it but every time I log on something sets it off and iTunes starts downloading this show again. What am I doing wrong? I can’t seem to get rid of the thing. Help!