Agree that reaching out to support should help - they're generous and pretty responsive
I think the best option here is to contact Oculus support. Ask them you tried multiple referral links and none of them work. Contact them today to see if they can provide you the $60 referral credit before it expires tomorrow.
edit: it is possible that the links here are only from the US and you are located outside the US like Europe. Hence, you are getting that error showing up. In that case, you have to look for a European referral link online.