K's correct. First step is to write them a demand letter, or have an attorney write them a demand letter, so that you can have a record of what you've previously requested and what remains unresolved. It also creates a record of what you've done to try to get them to correct the problem, and shows that you've tried to mitigate your damages.
If they don't respond or otherwise refuse to fix the yard, then you can pay to have it fixed yourself, but just know that you aren't guaranteed to be compensated for what you spent. You'd have to take him to court to request compensation, and even then, you'd have to deal with arguing whether you did your due diligence in finding a company/person to fix the yard for a reasonable price, whether you gave the first guy a reasonable amount of time to fix the yard, etc.
If it comes to the point that you have to take him to court, it'd be best to do so while the yard is still fucked. Fewer issues to address in court, and the damages are still easily proven.