Legal Question in Business Law in California

In terms of stopping the use of the name, you can file a suit for trademark infringment (either in federal court or state court, depending on whether the trademark is federally registered). If the name being used by the store is causing you damage you can get compensation. Showing such damage would be the difficult part, and depends on many different factors. Aside from the trademark issue, you could also sue on a breach of contract theory. Did the sale contract include a liquadated damages clause.

You should speak with an attorney about these issues, as your options will large depend on specific facts that could not be answered on a general website such as these.

The buyer's problem with the landlord is not your problem. He needs to pay for the awning or sign change, pay the landlord money for the right to change name, or whatever. You can sue for specific performance of the contract as well as the damages mentioned by Mr. Shem-tov.

The most advisable and practical remedy probably depends upon the relative urgency and importance to you of getting the use of the name stopped promptly. Your choices could also be influenced by whether stopping the use or collecting money damages is the more important remedy, and the amount of your provable damages thus far. In my personal view, pursuing a trademark suit is not the best approach, especially if the trademark is not registered with the USPTO; I'd go with a breach of contract action although it might be a good idea to throw in a common-law trademark infringement cause of action for good measure; there may be additional damages available that way.

So, I'd suggest a suit for breach of contract, permanent injunction, and infringement of common-law trademark. If fast action is desired (and the regular court process is slow), I would, at or near the time of filing the suit, apply ex-parte for a temporary restraining order (TRO) ordering the buyer/defendant to cease use of the name at once.

I would want to read the full contract by which the business was sold. Many lawyer-drafted sale of business agreements have specific provisions allowing a party to request injunctive relief for breaches. This is not a prerequisite to getting a TRO and then an injunction, but it makes it a lot easier to convince the judge that injunction is appropriate.

I agree that the landlord's position is irrelevant. The buyer is just making lame excuses.