Telus took money it wasn't entitled to and I can't get it back

I have had a home security account for many years.  Recently, Telus told me that it no longer supported the equipment I had and that I had to enter into a new contract with new equipment.   I elected not to do so and Telus cancelled my home security account effective June 1.   But then Telus issued me a bill covering service for June 1-30 and took the pre-authorized payment on June 18.    I cannot find a phone number to call and speak to someone about this.   When I tried the AI chat, it told me I don't have an account (even after I provided the account number) and said I can't speak to a live agent without an account.   What terrible customer service.   No wonder the share price has tanked over the past few years.  I just need a phone number so I can talk to someone to cancel the pre-authorized payment!