Why can't I downgrade?

I got my internet on a special 5 years ago. I originally wanted the lowest starter plan internet but the call person talked me into the special price which was for the internet essential which is aprox 20  month more  but would be faster for same price for 12 months at which time she stated I could switch to the lower price internet.  I have tried to downgrade my internet over the phone numerous times, by email, in person etc Am told that it's not possible with my  package.  My package consists of Cox TV Economy which is 40. plus a month.  I get limited channels.  I don't need this faster internet service.  I have never used the data or do I watch movies on line or gaming etc. That's why they say don't believe everything (or anything cox says)  Five years later and when I sit here and think of how much $ it has cost and I know that I would never have agreed to the "deal"   What a racket.