HUGE increase in data usage w/no charge in our home

Adding us to the list. We went from roughly 300GB/month to going over...no changes in our home. It's only me & my husband. I've been working from home for 14+ years full time & my husband started last year. We are suddenly receiving messages that we're approaching our limit. We were at 68 GB of 1.2 TB remaining as of a couple of hours ago. We stream a few shows/week & don't game. It's impossible that we're using that much data. I called customer service & tried the chat; both were useless. It's infuriating.