McLamb's Landscaping Co

I contracted with McLamb's to construct a patio. Shortly after completion, the patio started sinking. I have been unable to get them to repair it.I had been dealing with [redacted], President. I notified him in early November that the patio was sinking. He replied via email that he would be out the following week. He never showed up, again I contacted him. He again acknowledged that he would be out to do the repairs. Again he never showed up. Since then, he has not responded to numerous emails and voicemails. The original work was completed in late August. The sinking was identified in late October. I paid more than $15000 for this project and expect that he stand behind his work.Desired SettlementI want McLamb to repair the obvious defect in the work they performed. If they are unable or unwilling, I expect a refund of $3000 so that I can hire another contractor to complete the job correctly. A patio that was designed to serve as a parking pad to support a vehicle should not be sinking after a couple months.