Every ISP has had teething problems when they released new products so calm down and give it some time. If you don't like the service then move to another ISP instead of crying on every forum available.
Personally I have used 129Gb this month. I'm not sure about my download speeds because most of my downloads are scheduled for 12-6 but my WoW latency on 4 machines are always around 200ms so I am a happy camper.
All is going well for you - great. What is the point of forums if not to raise issues when they arise. Any good company would welcome feedback as this can only help to make them a better company.
How much time do you suggest then would be fair to give the company before complaining?
You are paying for a service, but hey don't raise any concerns if you are not getting what you paid for until a few months down the line. No offence to you, but this is why in SA we have so many poor businesses and service