It is possible there is some confusion with regard to terminology. I have a Comcast modem, that also happens to be a router, which I have no direct control over. But I run everything through my own router that I do have control over.
If you have a cable modem/router, you can usually do a reset yourself. Disconnect the data cable and the power cable. Wait 15-20 seconds, twist the data cable back on and power back up. Most of the tome that will work to solve problems with junk buildup on thew modem.