Can I stop a competitor using a name similar to my trademark?

As the holder of a registered trademark under the Trademarks Act, Chapter 416 of the Laws of Malta, you generally have the exclusive right to use your registered mark in relation to the goods or services it covers, and you can take action against a third party using an identical or confusingly similar sign in a way that creates a genuine likelihood of confusion among consumers, which appears to be exactly what you're describing given the actual customer confusion you've experienced. The first practical step is typically sending a formal cease and desist letter to the competitor, clearly setting out your registered trademark rights and the specific confusion being caused, and requesting that they stop using the confusingly similar name, since many disputes like this are resolved at this stage without needing to escalate further. If the competitor does not comply, you can pursue formal legal action through the Maltese courts for trademark infringement, seeking remedies that can include an injunction to stop the continued use and, depending on the circumstances, damages for any harm caused to your business, and documenting the specific instances of actual customer confusion you've experienced will be valuable evidence in supporting such a claim, so it's worth having a lawyer formally assess the strength of your case and prepare the appropriate correspondence and, if needed, court action.