SUPER SLOW INTERNET Belkin n750 dual band router?

[Steven Louise]

Hey, I have a belkin n750 Dual Band router. I called up time warner cable because my internet was super slow. They told me to connect my laptop directly to the modem and I had no no problems. My speed were 15++ and upload was 1++ since I'm only paying for those speed. After that they told me to connect my router to my modem and use wireless connection to see if my internet was still slow and after that my internet was slow again. The customer service said it might be a problem with my router. I'm a little computer geek so I know what I'm doing, I changed the channel to reduce interference with other router and I have the latest firmware update. Intellistream is off, I have security up with both of my channels 2.4ghz and 5ghz. I turned off the guest access to see if that will help but no. It didn't help at all, I just bought this router couple months ago. And the people from TWC told me to just buy another router but I don't want to waste my money. And I spent a lot on this router because I thought that it would give me good results. Should I buy a new router? And I don't know what to do anymore. I tweeked all the possible ways to speed up my internet, but still no luck. And sometimes my speed goes down to .50mpbs download which is very dissappointing but I have no problems with my upload speed. What can I do?