Internet issues

Does anyone else have issues with intermittent internet connection, especially during "prime time"(8-9 AM and 5-8PM)? The limiting of data during these times is of course illegal, but I am experiencing it on a daily basis. I have had multiple calls to COX tech support, but they insist there are no issues and I need to pay more per month to fix the issue (just upgraded last month with no improvements). I have also been told it is most likely a problem with my modem because they do not recognize it (they supplied me with it, and have serviced and replaced it twice). If you are having the same issues, let me know how you fixed them.