data usage

I have called at least 3 time and each time I get an overseas representative, they dont listen to the explanation that it is impossible that we used 3 TB of data in one month when our usage has been around 500 GB since the introduction of streaming. There was only one person in the house when it spiked to 3 TB, then only one person when it spiked to 1.4 TB. They do no investigation, they are not technical staff at all even though they say they are, all they keep saying is that we used the data, I keep repeating that it is impossible and the reasons why, they then say that it must have been a breach. I reply that if it was a breach this it is the Comcast modem that was breached. There is no investigation as to how this is occurring and at what time of the day or night to see if it is actual data usage by the homeowner. I thought that I would check if it is a common occurrence, it appears that it is a very common occurrence and the so called technicians know this but they keep repeating the same thing, it is our problem. It is impossible that so many users are having the same problem, it is definitely a Comcast issue that should be resolved by Comcast. We have been a Comcast are considering changing to fiber that has just been installed in our neighborhood, faster speeds and $50 cheaper per month and local too, no long wait times on the phone and having to talk to customer service people who dont know what they are talking about, just reading a script, technicians that are not technicians. I have asked for a tech  from the usa to call me back but so far after requesting one, no one has called. Reading the comments from others this is a huge problem that Comcast has left unresolved and it obviously angers all users like us because we have not used this data yet we are being charged for overuse of data.