UNHAPPY CUSTOMER

I never thought I would write this kind of review for you because I have been extremely happy with the network and customer service I have received so far until recently. I started having problems with connection about 2 months ago. I made a query about a month ago and got assisted by one of your agents, a nice gentleman who was professional. The problem continued and I made another query but still the same results. I just complained again today and I'm losing patience now because it's affecting my work but still not sorted and I feel like they are not understanding me. The last time this happened someone came and changed the router but now when I ask if someone can come to check this, I'm told that I will be BILLED. Why do I have to be billed when I'm not getting help on the phone? You don't have to change the router if it doesn't have to be changed but I need this sorted.