Reconnecting disconnected Game/App

I am currently a student writing my master thesis. In my master thesis I use work from previous students who created Avatars which we use in our experiments. We are facing an issue, where we cannot access the avatars that the previous student created. Now looking at the account it looks like there is no game connected anymore to the account and we also cannot access the RMP Studio. We assume that someone did it in bad spite. Would it be possible to reconnect the account to a Game/App that has been disconnected? Does anyone have an idea how to retrieve the avatars?

We do have the links but it always says 404 not found.