Dallas Automatic Gate, Inc False billing practices, deceptive invoicing Mesquite Texas

Called this company because we moved into a new property that had a box of their gate openers.  We needed more gate openers.  When I talked to "Micky" his phone cut out and the call was disconnected.  He had told me in the brief conversation to text him a pic of the gate openers I was calling about.  I texted him the pics of the gate opener, expecting a call back to know whether he had them in stock, pricing and delivery info.  His response to my text was "OK" and that is all I heard.  Next day, he shows up at my office, saying he wanted $600 for 20 remotes!  INSANE!  How about call me to let me know how much it will cost or when they would be delivered.  No one asked him to come in person, I figured they would be mailed or I would get a call asking for a credit card.  Now, almost 2 months later, I get an invoice in the mail with a "PAST DUE" stamp on it (first invoice I received by the way) for $135.31 for a service call.  What a rip off!  I never agreed for him to come out or asked for him to come out, nor did I agree to a $125 plus tax service fee!  Which is another thing.  Since when do "SERVICE FEES" require tax?  You don't tax a service!!  RIP OFF!