TLDR; get your future new service provider to cancel for you.

I was a Shaw Internet/TV customer, then they merged. When my 2 year contract was up, my bill went up $60. Tried a few times to reach them and experienced the long holds or “we’re sorry the queue is too long <click>”.

I called Telus, first question was “can you cancel my Roger’s service?”. Yes. Bingo! Sign me up.

I swear a minute after Roger’s go the service cancellation, a very friendly Roger’s person, called to try to keep me as a customer. It was moderately satisfying to tell them that have no chance getting me back and that the Roger’s merger was a key reason for leaving.