Extremely annoyed with web Africa and a waste of money , I have a issue with them after purchasing a 1 Gig fibre package and I'm not even getting 400 mb download speed

Extremely annoyed with web Africa and a waste of money , I have a issue with them after purchasing a 1 Gig fibre package and I'm not even getting 400 mb download speed. This has been going on for a long time now and want to cancel with them . I am done with them.