Pointing fingers when they are supposed to be in control of fixing the problem?

Very disappointed. I call them once a week to fix my LTE-A Line speed that is constantly running underneath 5mbps download and my upload is 25mbps. The last few days have been worse, my download has been running at 0.33 - 1mbps and my upload is the same 0.50 - 1mbps. Every time i call them they tell me its should be working and if not to call them back when i call them back to tell them it did not work they tell me "Sorry can't do anything about it" due to Cell C the network provider. One consultant told me that my line speed should be a minimum of 10 mbps download. I don't expect my speed to be running at 30 or 50 mbps but i do expect it to run at 10 and up.