It is possible to stop someone using a similar trademark to yours on their goods and services but is harder to defend unregistered trademark than a registered trademark. You have to be sure you will be able to show that the mark is yours, it enjoys copyright protection, i.e. it is original and has been created by or for you, you have built up goodwill associated with the mark and you have been harmed in some way by the other person’s use of the mark. In any case, some jurisdictions will not allow you to defend your rights based on unregistered trademark even if all the above exists.
