Overcharged internet without notification

Hello,

I'd like to share my experience with Videotron internet.

First of all, we have been a user of the internet of Videotron since 2016, which has been long enough to be a loyal customer. Over the years Videotron kept changing their internet plans/monthly rates, which got cheaper.

However, since 2022 somehow we have been overcharged monthly amounts of the most expensive internet plan GIGA while our plan has been Internet 60 (minimum cheapest plan).

We have never received any notice of rate changes from Videotron, finding those overcharges by chance.

So we contacted customer service and asked them check our account, and they immediately found those unfair charges and modified the next bill amount. As for all the overcharges, they said they would contact us again less than 48 hours, but we had No call, No answer, No letter from them.

How can we ask them refund us fairly?