Concert tickets bought online never arrived and organiser went silent

This looks like a straightforward case of a trader failing to supply goods or services that were paid for, which falls squarely within the protections of the Consumer Affairs Act, Chapter 378 of the Laws of Malta. Start by sending one final written demand, by email and, if you have an address, by registered post, giving a short deadline to deliver the tickets or issue a full refund, and keep a copy for your records. If you paid by card, contact your bank about a chargeback, since unauthorised or undelivered goods and services are common grounds for reversing a card payment. In parallel, you can report the trader to the Malta Competition and Consumer Affairs Authority (MCCAA), which monitors unfair commercial practices, and if the amount involved justifies it, file a claim with the Consumer Claims Tribunal to formally recover your money. Keep all payment confirmations and correspondence as evidence throughout.