Shred-It Usa Llc

They were supposed to call me at home when they were on their way to the store.  We had recently closed our store, and all the old files were next to the front door ready to be picked up and shredded.  They did not call ahead of their arrival.
Their salesman came the week before the scheduled day and gave us an estimate of $650 for the job (12 totes) and said they would send a crew, since there were so many boxes of old files.
 I received a call on that morning saying that they had been waiting at the store for me to show up.  Had to forget breakfast and brushing my teeth etc and hurry to meet the ONE man who came to do the job.
I was told by him that the estimate of 12 totes was way off - he filled 16  totes and had to take 21 smaller boxes as well.  He would not take them all unless I paid him $1033, which I had to do since the auction of the store was in two days and the store had to be cleaned.
A week later I received an invoice demanding payment.  They had received my check from the previous week (which I had given to their employee) but not posted it, I guess.  And the amount of their invoice was less than what I had already paid.  Supposedly I was to received a refund of the difference.  This has still not been received a month or so later.
It is now six weeks since the work, and we have not yet received the Certificate of Destruction either.  I have called about this and was told that they would email it to me.  We will see.