pathetic service

I took a wifi router on contract for my son, which is for 10G of data for the month, 2.5G during the day and 7.5G at night. It worked well at first but for the last 3 months or so my son says he could no longer use the night surfer, firstly they have moved the night surfer hours without informing me secondly they give different excuses. He's constantly trying to get it to work, he had called the call centre twice and still no luck only stupid excuses as to why he can no longer make use the night surfer, I still get billed the full amount every month but don't even get to use the night surfer, the call centre gives 2 different explanations and its frustrating that no one can actually help. Not to mention that the signal is really bad all of a sudden. Can someone give me a straight forward answer instead of beating around the bush....after I signed the contract its like they don't care about the service I receive.