C3000 - Internet is very slow

I have big issue in connecting to internet for last 2 weeks. Wifi is connected all the time but no Internet. When i reset the wifi router it will work for some time and then disconnected, some days are terrible i have to reset router mulitple times. I tried changing to least busy channel, still i get into same problem. I called the cable provider they confirmed there was no issue in their side. 

Please advise is there anything i can do to fix this issue fully.

Thanks.