So I had a couple interrested buyers in an sr ibanez bass this morning that's been in storage for about a year. I pulled it out and it was tuned down so I started tuning it to pitch. While I was tuning the g string, I heard a snap and the tuner stopped working

I took the string off, and the middle part of the tuner fell out. Just my luck lol. I can screw the piece in but as soon as the pressure of the string goes on it it goes loose again. What do I do?