Billing issue

I have two lines with Telus. Each of them is on a $55 plan. Each plan should be discounted by $10 per month for 24 months, and each plan should have a further $10 discount for pre-authorized payment. When I called support they assured me that this was the case even though it didn't seem to be when looking at my bill. Now that I've received another new bill it's obvious that a mistake was made. When I try to make support requests in the app they are closed within a few minutes of having made the request. I could really use some assistance here to resolve the issue both for past bills and future. Thank you.