Why does my wireless keep losing connection with charter?

I know there are dozens of older posting for this and I have tried them all but nothing has worked and I hope someone can help because I have everyone around me stumped. I dropped ATT on the 16th of this last month and changed over to Charter Commutations. They supply the modem and I buy a wireless. Last Friday my internet just started dropping right out of the blue and hasn’t quit. It drops when I am on my PlayStation but yet I still stay login in, I can’t figure that one out. I loose connection on all computers and phones all at the same time. It will be just random, sometime it can be a few second but it can be up to 30 min. Charter has been out to the house several times and can’t figure it out, they say it the wireless and to buy another one. I went and bought my third wireless today. I talked to a few guys at BestBuy and they couldn’t offer any help. I bought the Belkin N750, once I set it up the stream was great for 2 hours, then it was back at it again. I have computers that have windows Vista and 7, along with all the gaming systems and it happens to them all. I was just in Belkin control panel trying to change my channel again and my internet was gone but Belkin said it was connected.

With everything advancing so fast I barely get by with computer technology now days, but I just know there has to be some interference or some kind of connection that’s either off or just plain wrong. It to the point that I’m going nuts; I can’t play my games or do any of my work without it dropping. I would very much appreciate any help, since Charter can’t offer me anything else.