Benni, i had simila problem but with signal loss, i complained month in and month out, in the end i decided to tell them that THEY have caused breach of contract by not providing ME with a service i'd payed for, tell them when you conplain next , that you want it esculated to the next level and you want someone to phone you back within 1 day with an answer to your problem, ie a result, not an exuse.

When you finaly get pissed off with them talking shite tell them you want to terminate the contract because of the said breach on thier behalf, so its thier fault not yours, if you stop paying them, they win, so keep paying them till you get an agreement that youre happy with.

It worked for me i got out of an 18 month contract after 11 months.

They bulshitted me all over the shop mate, in the end i got out of the contract with the phone also.

Be persistant mate you will win.