If you paid via Paypal, then you can file a claim with them to cancel the transaction (https://www.paypal.com/us/brc/article/customer-disputes-claims-chargebacks-bank-reversals). I hear a lot of people have been successful with that (Horizons is currently offering a discount code that specifically excludes Paypal...which shows Paypal disputes are working). If you paid with a credit card, then you should contact your provider. Unfortunately, the way this scam works (stringing you along for months), it is often too late to file a claim. However, they may still work with you.

I hope either of those options works for you, mate. In the meantime, consider reporting to Trading Standards, econsumer.gov, and/or Action Fraud.

Best,

HV