Maltese License: MGA/B2C/145/2007
Authorisation Type: Type 1 Gaming Services, Type 2 Gaming Services, Type 3 Gaming Services
On the https://www.mga.org.mt/support/ there’s an Online Gaming Support section on the top left , designed for Players to report License holders for misconduct.
If your claim is indeed legitimate, they’d be warned, fined, may even lose their license.
The beauty of casinos holding one of the more reputable licenses is that claims are not ignored and they take them SERIOUSLY.