Five Star Capital Quoting for closed end lease, then claiming the contract is a rental agreement San Diego, California

Five Star Capital solicited a 3 year closed end lease from us on a Autometrix Cutting machine costing $38213.00, competing against our usual leasing company LFC of Denver. We signed the lease for the 3 years and paid 36 installments
of:$1280.49 which they accepted plus insurance.

 Lease Services ACH 110301 0363651655001
Michael Stevens 1,280.49 Total $46097.64
Now they are claiming an additional $15341.83 after the equipment has been fully paid for.
We have had 8 leases with General Electric and LFC leasing on equipment over the last 25 years in business. They have all been closed end leases with $1 buyouts and we told Five Star Capital that is all we wanted and they were competitive on that basis. We signed a one page lease to that effect, now they are suing for the balance.