Unscrupulous Security Tech Charges

I did not want to renew my Home Security account as I had not used it in sometime. The sensors were also broken. TELUS sent over a repair person to exchange the sensors. He arrived and replaced all the broken ones. He said that there will be a charge but to call into customer service and they will reverse it.

Today I received a charge of $400. No one is reversing it and saying I approved it.  This tech was named LUCKY and left his TELUS card and phone number. I need this reversed or will have to cancel all my TELUS services as it has not been 30 days since the new contract.