Does not paying royalties constitute a breach of contract?

You should contact a lawyer, show them the contract, and let them help you. I do this very kind of work and so do many other lawyers. No one can really tell you if your contract has been breached if they have not even seen the contract. Also, what you are experiencing could possibly have been avoided if you had the contract looked at and changed a bit before you signed. Most likely, you should act quickly on this, because it sounds like you are acquiescing to not being paid. In any such a contract, you should have a clause that says you are entitled to an accounting every so often, so you know what sales have been made and how much you are to be paid. Most such contracts also have a threshold in sales that must be met before you are paid. The company will usually wait until the royalties add up to a certain amount before they made a payment. Also, if you took money upfront, you should have specified that was not an advance against royalties. If you took an advance that is recoupable from the royalties, it may be that you are still paying that off. To find out about all of this, of course, I would need to read the contract that you signed.

This depends on a number of factors. First and most importantly are the specific terms of your contract with them. Generally speaking, if there were royalties to be paid which were not, you can likely use this as grounds to terminate the contract and sue for breach of contract. You should have the contract and relevant facts reviewed by a qualified attorney.

Paying royalties in a distribution contact is a key term in the agreement and can definitely constitute a breach if royalties are owed. These are complicated situations. Have they tried to distribute, are they simply withholding or not paying? There are lot of questions to be answered before you know if you have an action in your case.

Failure to pay royalties that are due is a breach of contract. Check your original contract to see what the specific terms are for payment and whether the distributor has the right to assign or sell the contract to another party. Then contact an attorney to send a notice of breech/cease and desist letter requiring immediate payment of past due royalties and notifying them of your intent to terminate the contract. You may be able to negotiate better terms if the company really wants to continue distributing your product.

Their failure to pay royalties is certainly a breach of contract on their part. Whether that gives you the right to cancel the contract depends on what the contract says about what legal remedies you have. It would be worthwhile to have an attorney review the contract to determine your legal rights.