Unable to cancel contract due to an unavailable retentions department during their own stated business hours

A few months ago I called the customer service department to enquire as to how and when I would be able to cancel my contract. The agent advised me that I should call in again a month before my contract was due to expire. I set a reminder on my calendar and called a few days early, just to be safe. I was given the number of the retentions department (084143) and was told to phone 2 days later, before 6pm, I phoned on 2 May between 17h30 - 18h00 and got an electronic voice message stating that I had called outside of office hours and that they close at 6pm. I sent an email to customer service stating my problem and that I wanted to cancel my contract but, to this day, nobody has contacted me in this regard. I then called again the next day between 17h00 - 17h30 and got the same message! How is it possible to call outside of office hours when I am calling before 6pm??? I then called the customer service center again and the agent told me that the retentions department is not always available and that I can go into a store to cancel my contract. I went to the Kenilworth Centre branch the next day and was told that they don't do cancellations in store. I finally got through to the retentions department on Monday, 6 June and was able to cancel my contract. Unfortunately, because it was now less than 30 days before my contract expired, the cancellation can only be effected in the next 30 day period and I have to pay another whole month. What a waste of time and money...