ugu's poor service delivery

I have been trying to get hold of ugu to have a tanker come out and clean our septic tank, but their phones just keep on ringing. I have also emailed them for a reply, but to no avail. My major problem/concern is that I pay my monthly water and sanitation fees religiously but dont get the service I pay for. But if I dont pay my bills, I get blacklisted and the party who is in the wrong gets away scott free. If I pay for something, I expect to get it, but if I dont get it, I dont pay. Isnt that how it should work. Instead if I dont pay for the thing/service I didnt get, I am in the wrong and gets blacklisted. What do I do in a case like this. If I could, I wont pay and they dont need to service me and I would become self sufficient, But then I suppose I am in the wrong by not paying my account for something I didnt get.

What to do? What to do?

Hendrik