Sorry to hear your having such issues. Intermittent problems like that can be the most frustrating to deal with. Intermittent drops like that can definitely be caused by a bad cable, you get a loose connection or one of the little wires inside is partially broke and the slightest movement could cause it to go up and down so it does sound possible in that respect. With that being said however if someone else in the same area is also having an issue it may not hurt to get a second opinion. Now this doesn't mean for sure there is an area problem and it could be a coincidence but who knows. Maybe try giving our tech crew another call, or even chat in if your connection is up long enough. They may be able to see something new that the previous agent didn't that might help.
Went through a similar issue.
It is possible there is an app such as iCloud, Dropbox, or similar that automatically copies larges amounts of data to the internet running from a device you or the people you live with own that is saturating the network. This could include torrent apps commonly used to download tv shows, movies, and music. Another possible culprit is a "free tv" box/device.
If you wanted to try and troubleshoot this further hunt down every internet connected device you have and disconnect them all from the network. Leave a single device on and check if the problem is still there. If it goes away bring devices back online one at a time and keep checking them.
Yes, it is a pain to go through all this but end of the day if MTS sends out a field tech they are going to go through all this with you.
Also if you haven't already done so it would be recommended to call this in to technical support 204.225.5687
Do you have landline voice service and is it noisy ? If so it could indicate a problem with the line serving your residence.