Constant high packet loss, also none existent upload speeds. Had 3 engineers out.

I'm getting constant packet loss, which I think is why my upload speed is none existent (1000/100 package) I work from home and need the upload just as much as I need the download.

3 engineers later, telling me all the wiring and router are fine, I'm still having the same issue. What can I do at this point but not renew my contract and try my luck elsewhere?