ATT High Speed DSL slow?

Just recently the DSL in my house has become very slow, I play Xbox Live alot and I keep getting connection issues plus my dad is getting problems with his connections as well. I've heard ATT customer support is crap, anyway to get our speeds back up to par? We use a Netgear router thats has 5Lan connections that branches off to a Lynksys router and to another Dynex router to my room.