Iburst
Repeated complaints not attended to

My name is Mortimer Petersen acc. no. W0189014.
I received bad reception using my Iburst modem, so much so that I could not complete University assignments.
I complained to them continuously, but to no avail.
Now my Router is malfunctioning and after repeated phone calls and sms's I get no response from them.
I don't even get any advice as to how to correct the situation.
Please advise me further as I am desperate.
Thank you
Mr. MCJ Petersen