Tt&t Disconnecting!

OK, I know we've had this before and I know I'm too far from the exchange etc. but at night my connection to ADSL goes down every 5 minutes to the second. I know it will go down from time to time, it does in the daytime, I've come to accept this now although it will keep connected longer but I just can't understand why at night I can count off the minutes to 5 and "Down" it goes. Is there a sinister reason at the back of this? Is there a little man at TT&T with a switch in one hand and a clock in the other just waiting for me to get my 5 minutes worth and then switching me off? I don't know how long this has been happening, weeks, months, I only notice it when there is not a decent movie on UBC!