Store says I need to file an appeal to buy stuff

If you have other accounts such as Facebook, Instagram etc linked to your Meta Quest account, try unlinking them. Otherwise, you can email or chat with support here. Or send a message to MetaStoreHelp​ .

It's a broad issue. More posts here:

We noticed something unusual and for your security, this request couldn't be completed. | Meta Community Forums - 1172180

Unable to purchase games – “unusual activity” block | Meta Community Forums - 1358090

We noticed something unusual and, for your security, this request couldn't be completed. | Meta Community Forums - 1340120

Unusual Activity | Meta Community Forums - 1337094

"Unusual Activity Detected" error has stolen 6 hours from my life. :( | Meta Community Forums - 1342878

Can't buy any games it keeps saying suspicion activities and to file an appeal | Meta Community Forums - 1336409

Don't use social media