Family sharing/Apple Music

im a member on my grandmothers family sharing set up and she shares her Apple Music subscription with me and my dad. Recently I was unable to use my Apple Music, when I open Apple Music it shows me different plan options and won’t let me listen to music anymore. I called a few time to Apple trying to get it fixed, one of the tech supports said she fixed it but it still wouldn’t work even after restarted my phone. I had my grandmother delete me from the family sharing and send me an invite to have me Join in again but whenever I open the invite, it brings me to a page where nothing happens. I’ve tried restarting me phone but nothing seems to change the page. I had my grandmother send me another invite but it would let her because she already sent one. Why is it not working?