property manager failure to notify owner - rescheduling of vendor

[Account Closed]

I am stationed outside of US and have a house rental, managed by a property management company in Brandon, Florida. I have been arguing with my property manager (PM) regarding the cost of their vendor's bid for $1,325 for fixing plumbing repairs in my house. Without agreeing to this amount, I have unfortunately asked my property manager to send me in April 2014 an invoice for plumbing repairs and scheduled the plumber to do repair work on May 27 2014. I planned to meet with the plumber on that day to tell him to repair only some of the plumbing work and negotiate the costs. He did not come. On May 28 and 29, I emailed the PM that due to the failure of the vendor to arrive on the schedule date, the PM should not reschedule the plumber and cancel his services. I did not hear from the PM until June 6, writing to me that the vendor had repaired some of the plumbing work for $1,325, attaching the vendor's invoice with photos of what he did. I told them that my latest instructions, i.e. not to reschedule the plumber/cancel his services, and that I did not explicitly agree with this amount. However, the PM told me to pay the full amount but I offered to pay half of the amount only. They insisted I pay the full amount. Am I right not to pay in full the amount as the PM breached their legal responsibility for not following my recent instructions to cancel the vendor's services and their failure to inform me of the rescheduling and that they should actually shoulder the costs, at least half of the $1,325? They threaten me that the vendor would be running after me with fees, if it is not paid in full.  Appreciating your advice.