Disappointing service of late

Sonic Herotel's service used to be fantastic. However, over the past few months the service has deteriorated. We pay for an internet speed of 10 mbps download and 3 mbps upload. However, of late we only get around 2 to 7 mbps download and 1.5 to 2.5 mbps upload speeds. Whenever we lodge a complaint, they don't warn us when they will be cutting out internet off to check the problem, they simply cut it to work on the problem. This is very disruptive as we are often in meetings and suddenly, no internet. Very unprofessional for us as we are usually in client meetings and this does not bode well for our business. What makes matters worse, after working on the problem, our internet speed is always lower, not better. So frustrating - we end up with backwards and forwards emails to try to get them to resolve it to the speed we are actually paying for. We need a reliable internet service provider and sadly Sonic, who we used to rave about, is letting us down a lot.