If the ISP was a customer buying bandwidth from Comcast like anyone else, then Comcast has zero obligation to increase their bandwidth for free. If the ISP is

If the ISP was a customer buying bandwidth from Comcast like anyone else, then Comcast has zero obligation to increase their bandwidth for free. If the ISP is Comcast, then when you pay for that 1Gbps uplink, you are paying Comcast and you have a right to expect that your packets will be delivered at that rate. If the ISP is a peer of Comcast, then it seems like when you pay that ISP, you ought to know the exact details of the agreements and bandwidth arrangements between the ISP and Comcast, and both parties ought to abide by that contract. I don't know enough details in this case to know whether that's what happened.