D2R game removed from Battlenet account

I wanted to play some D2R, which I haven’t played in months, when I tried to load my game, it said I had been offline for more than 30 days and had to load the game in online mode. My internet connection was working fine, and I found a few posts with the same issue, none of the fixes in those posts worked.

My next step was to uninstall and reinstall, but now Battlenet says I have to buy the game again. Please help.