Sirius XM radio Scammed renewal period and unauthorized automatic checking acount charge other 

I received 6 months Sirius radio satellite service when I purchased my car in 2016. I called Sirius twice to renew, each for 6 month periods. I let the 2nd renewal (due 4/2017) lapse until July 2017 and called Sirius to renew for 6 more months. Their agent did renew me for 6 months but made 3 months retroactive to April 2017. Then the service quit working December 26th so I called Sirius today to get help and was informed that my checking account was sutomatically charged October 3, 2017 for only 3 months and the fee is now due again. I never agreed to be charged retroactively for 3 months and never agreed to have my checking account automatically charged. This account is rarely used so I missed the automatic charge in October.