Landscaper accusing us of breach of contract

Oct 2019 we signed agreement for a paver patio. Contractor wanted $5000. to start and $10,000. to buy pavers. We paid him the $15000. His workers did 5 days worth of work in Oct.- he was to finish in December, but told us pavers on back order. Put it off till April 2020, as we go to Florida for winter, which he knew. Came back and he blamed Covid for lack of workers. He apparently does not have a crew and hires day labor. Found out he did not buy pavers we ordered and the 5 days of work was done incorrectly per several other contractors. He refuses to give us pavers or our money back. We are willing to pay for the 5 days of work, even though it will need to be dug up and started over, and then move on from him. He sent us a breach of contract letter on personal stationary. We think he is in breach since he did the work incorrectly and did not follow the specifications on his contract about material amounts and placed a concrete grade beam in the wrong location.