Existing Clients Overpaying

I am so disappointed with Supersonic. I have been a loyal client for many years, since fibre was installed in our area. I am currently on a 30mb line paying R899pm. I was disgusted when a friend, who is a Supersonic client, is paying R695pm for a 35mb line. This was only by chance that I found out about the cheaper prices. Supersonic does not inform existing clients that they offer cheaper packages for the same speed or upgrade my line speed for the same price. I have effectively been paying R200pm extra for a 30mb line which is offered cheaper to new clients for not sure how long. I am on a month to month package. No, Supersonic you robbing your existing loyal clients, I stuck with you even though you no longer rated as a top ISP. It is only when the client call in that they migrate you to the latest offering.