Avery Air Conditioning & Heating Air Conditioner problem with billing Houston, Texas

 I have a rental property in Houston and the AC went out.  I asked the tenant to call a AC company and get an estimate on repairs.  He called Avery Air  who said that repairs may make it last a few months but it should be replaced.  I choose to have it replaced since I knew it was very old.  They gave a written estimate to the tenant and I spoke with them by telephone.  They replaced the unit, called to get my payment info; however, they have not sent an invoice or receipt as of today.  They charged my debit card twice and it took over a month  and many many calls to get it refunded to my card.  I had the city to come out and inspect it and they had used the wrong size drain pipes and a couple of other problems.  They did send someone out to make those changes after many calls.  This took place on 13 June 2012 and I still have not received any paperwork from them about the warranty or anything else and we are now in 2013.   Very, very unhappy with their service.