Edited:
Met with Devin today and worked out an agreement that was agreeable to both parties. Overall, we are very happy with the work, and they have notated our account to prevent any future unauthorized work from being done before it is quoted and pricing is approved.
The work that was done was fine, but we were originally quoted $1300. There was some additional work that was suggested by the technician, which is also fine. However, there was no discussion about the cost of that additional work. We later (as another reviewer noted) had to ask for an invoice, and it was $7200.
I feel that an increase of more than four times the original estimate should warrant a discussion about the increase in cost. One of our representatives did authorize the additional work, but the responsibility to inform us of the additional cost lies with Vortex, and that did not happen.