I thought Mega introduced limits on there free accounts a few years back?
Pretty sure i remember people going nuts on reddit that it's impossible to actually use the 50GB?

1.-Mega Free - 50 GB *
What's the catch ? Bandwidth is severely limited overall (upload/download) *, on average ~ 1 GB every 6 hours. So forget about uploading/downloading files larger than 1 GB and large files in general. It will take you on average 12.5 days to upload 50 GB (4 GB per day) and another 12.5 days to download 50 GB, so plan is useful only for small files and limited traffic.
https://www.cloudstorageoptions.com/free/
Just found the above site , you're lucky not to be restricted , maybe it only applies to new accounts?