Terribly slow home internet

Only reason I give a 2 is because I am very happy with Vodacom in general. I am on the 100mbps home internet LTE. For the past week+ I get speeds of around 6/7mbps IF I AM LUCKY! Problem is definately not on my side since a friend of mine who stay 400m from me is having the same problem. To send a simple whatsapp message take up to 20seconds. Come on Vodacom. Get your act together. If I only pay 6/7% of my bill you will obviously be unhappy and take legal steps...what is different in my situation receiving 6/7% of the speed?