Connectivity Issues-ONGOING

We've had ongoing connectivity issues.  Consistently slow download and upload speeds, with multiple calls to customer service and several service calls to our office to tell us it's not your issue.......  We've never EVER received the speed we are paying for and no one at Comcast will follow through to help us resolve the issue.  The past several days it's deteriorated to the point that we're having to reboot early in the morning, whereas it used to be mid afternoon.  Something is obviously amiss and we need help that won't end when the phone call does.