Technically Put ! From all the documents I have read,
It seems to me that the law has been well established on the matters to be addressed.
First and foremost, failure to pay partial contractual payments does not invalidate, terminate or repudiate a contract, especially when a party to the contract objects to any termination.
The fact that Zone went to the trouble of having all the claims fully registered into Zones name; clearly demonstrates Zone intentions to maintain and enforce its binding contract.
Zone actions will speak clearly to this issue at law.