XM Satellite Radio Informative - Canceling XM Satellite Radio
As relentless as XM Satellite radio is to having you renew your subscription after your complimentary term expires, they are almost impossible to contact to cancel the service. They will, without notice, deduct payment from whichever account they have on record.
After being put in the 'on hold loop', the 'system is down, call back in 2 hours' loop, being hung up on and spoken to by people who speak accented English, I finally phoned the auto complaint line for my 6 month old vehicle. The service representative there was most helpful, actually spoke to someone with XM Satellite radio who accepted my cancellation. Of course they offered me continued service at a cheaper rate and several other 'come ons' which I refused.
Best advice for quickest response, call your automotive complaint line. They actually own a share of this radio service per the 'help' person.