Mine was suspended for spam and I was falsely accused by Mailgun of have compromised servers. Initially I freaked out and then discovered that my servers were fine, but my account at Mailgun was hacked and used to send thousands of spam emails. This happened a couple of times. I asked to see the IP addresses of the senders and Mailgun said they didn't track that/could not tell me. And then they had the audacity to bill me for sending spam that was sent as result of their system being compromised.

Dispute with your credit company. Tell them you did not agree for this service. Easily to recover the fee.