Spirit Airlines / unauthorized credit card charge

My credit card was charged on 10/25/18 in the amount of $9.00. I have not flown with this company since 10/01/18. I have contacted the customer service line and to no avail they are stating that they cannot see the charge. My credit card is showing the charge with a reference number that I provided to supervisor Michelle #31052. I'm looking for immediate reversal of this charge and any fees my credit card company accesses because of this. Prior to this charge, I was sitting at a $0 credit card balance. I have my onboard-inflight receipts and luckily I paid with a different credit card. The card in questions shows no onboard-inflight charges, however the reference note on my credit card statement shows onboard charge.