Business ProfileforBuffalo Chimney

We spoke with Craig on the phone and hired Buffalo Chimney to put a chimney liner in at my mom's house. After looking at the chimney, Craig explained that it would need a slightly more expensive double stainless steel liner (I'm not sure exactly how he described it--which is one reason we want an invoice) but that it would have a "lifetime warranty". We said fine, and they came back to do the liner. I spoke with Craig on the phone but my mom was home when the work was done. When I called Craig after they'd done the work to ask for some kind of receipt or invoice in writing for my mom's records, and for warranty paperwork, he said he was on vacation in Key West, and that he'd actually given the work to Nick, and to call Nick to ask for the receipt. I did, and Nick said he was waiting on back-ordered warranty packets. When I called later to ask again, he answered with a joke name, then wouldn't answer my calls. When I called Craig again he said he was still in Key West and questioned me about what we'd paid and said to call back in June when I had documentation, said he'd already given a receipt to a brother because I was out of town (which is not possible), said to stop calling him. I sent an email and got no reply. All I want is the invoice detailing work already agreed upon, paid for, and supposedly completed, and the paperwork for the promised warranty. If the work was completed and done correctly, why is Craig or Nick unwilling to put it in writing?