Sudden Spike in Data Usage

There are dozens upon dozens of closed topics with this same subject line with hundreds of people all reporting very similar experiences and no fixes, just upselling. My data usage is typically 400-500gb. In March (6 months ago) I had to upgrade my modem to the new Gateway package with faster download speeds - from 200GB/s to 400GB/s. I was still consistently using 400-500gb of data every month. Then suddenly in July, it ballooned to 1000gb with zero change in habits or devices. Then August it was 900+gb and two weeks into September, we've used 95% of our data. We've never come close to going over and now suddenly, these huge spikes that many customers are experiencing. I reached out to friends and family and those with Xfinity have or are experiencing this too. From the comments, customer service can't provide detailed usage per month and they typically just try to upsell you to unlimited speeds. Our habits and devices have not changed but I have a little less than two weeks left and only 3% of my data remaining. We're definitely going over this month. I'm not looking forward to trying to resolve this issue as contacting Xfinity is worse than getting a root canal.