Line speed pathetic

I am trying to contact Mweb due to my line speed, I pay a lot of money for 50mbs upload and download. My download sometimes scarcely reaches 20mbs. As I am also working from home this affects my work performance. It is impossible to phone them, you hold on for 29minn28s twice just to get cut off. Also, if you log an electronic enquiry they simply ignore it. The only people you can get hold of is the Sales team. Are you going to refund me with the service I am receiving vs the service I am paying for. Also