Tv and internet issues for the last month.

For over a month now our tv works for a little bit then will tell us that we need to tighten our cables which may fix the problem. Of course this does not fix the problem and then I reboot only to either have it work for a little while before same issue. I have replaced the box recently and had a technician come out and said the cable is fine so I am not sure what to do next. As well to be expected with the cable having issues the internet is also going in and out couple times a day. I just bought a new modem/router for around 400$ so I know its not my equipment. I am starting to think that the service that I have a contract for is going to continually be a problem. Any ideas or if anyone from cox can help that would be great.