Anyway, it's important to frame what happened correctly: the security of someone on your team was sloppy, and most likely a bot was able to get an access key or access to one of your accounts, spin up crypto miners on EC2s and now you're responsible for the bill. If it hadn't been that, it'd have been ransomware, you probably got lucky.
Now, to see if your situation can be improved: Put up some dollars and get business support. Make a clear and polite case, from the beginning. Ask for a refund but you don't have grounds to demand it; if they issue one, it's a gesture of good will. They probably will issue one if you haven't had to ask for that before, but it reflects badly on everybody that cryptominers weren't caught for two months.
And before you create that ticket, make some billing alerts so you can show AWS support that this won't happen again.