I'm in the same boat. Ordered yesterday, no email.
I called phone support and said they couldn't help without a order number and I should try chat support (which doesn't exist due to covid).
I rang again and was told to wait a week. If you SIM doesn't turn up then they might be able to help get you a refund.
Alternatively, you could work with your credit card company to get a refund directly. It's very annoying. I sent a complaint through here:
For anyone still struggling with this, here is how I solved it:
I called boost support again. I told them the situation, and again they were unwilling to give me the order confirmation number (it had now been over a week since I bought the sim and credit). However the rep said if I bought a $2 sim they could transfer the credit. They gave me a help request ID code. I also asked for the rep's email address. Once I bought the sim from a newsagent I emailed the rep. They then transfered the money I had spent onto this new sim, activated the service and ported my old number to the sim - done.