Pathetic customer service!

I contacted DSTV regarding the slow internet connectivity. The gentleman who assisted me suggested that I should switch it off, take out the sim card and insert it again, switch on the router and reset it. I've done this more than 3 times and still the internet is slow. When I contacted them for the second time the agent told me the same thing and suggested I should move the router to a different location in the house. I did that and it didn't assist. I called for a third time( already annoyed) and they now asked me to take the router to DSTV office for testing. I got to the office and it was closed without any notice. As it is now, I paid for a service that I'm not using.