Product: Vehicle loan or lease

Chase Auto has been slow to act and consistently misled us for the last year. 
This issue relates to the personal property tax related to a vehicle we are leasing through Chase Auto. Chase has failed to address this issue despite us contacting them numerous times over the last eleven months. This now has become urgent as the lease ends on XX/XX/XXXX and we want to buy the vehicle. Chase is telling us to pay the incorrect, higher bill in order to buy the vehicle. The total billed is ~ {$560.00} including ~ {$290.00} for XXXX and ~ {$260.00} for XXXX. The correct prorated would be ~ {$160.00} ( XX/XX/XXXX through XX/XX/XXXX. 
Here is the background. We moved from XXXX to XXXX in XX/XX/XXXX and registered our vehicle on XX/XX/XXXX. The tax bill should have been subsequently prorated to align with the portion of the year we lived in XXXX. We began contacting Chase Auto in XX/XX/XXXX. They informed us they would contact the taxing authority ( state of XXXX , County of XXXX ). Given this is a leased vehicle, the taxing authority and the department of motorized vehicles typically will not work directly with the end customer. We followed up with Chase a few weeks later and were told they were waiting to hear back from XXXX. We called several more times over the next few months and were told the same thing. Finally in XXXX, Chase informed us they needed additional documentation to prove that we moved. We quickly provided it via their secure messaging system. We again continued to call into Chase every few weeks to get a status update. Again, they told us they were waiting on XXXX. In XX/XX/XXXX, we received a letter from Chase stating that they began contacting XXXX to correct the personal property tax amount ( prorate for XXXX ). They repeatedly could not or would explain to us why they waited until XX/XX/XXXX to contact XXXX with the documents we sent them in XX/XX/XXXX. One representative told us just to pay the inaccurate bill so they would not hurt our credit. She was in possession of documents proving the bill was wrong and she told us to pay it or else. This issue has gone on so long that Chase just sent us a personal property tax bill for the calendar year XXXX. 
With the lease-end quickly approaching we continued to call Chase and they continued to tell us XXXX had not responded. I finally reached out to XXXX myself and explained what Chase was doing to us. They surprisingly told us that the account was updated ( prorated ) in late XXXX ( two months ago ). I have contacted Chase several times over the last few days. The agent continues to tell us that they will look into it. I asked to be escalated to a manager who promised she understood the urgency ( 3 days before lease-end ) and she said she would investigate, expediate and call me back by XXXX the day after ( XX/XX/XXXX ). She never called. I then called again and was told once again they would look into it. This supervisor expressed no sense of urgency. I have emails from XXXX both confirming the tax bill was updated and providing contact info that Chase could call to verify. Chase will not take this information and contact XXXX. 
Chase will not escalate my issue any further. They keep telling me to wait for them to get back to me, but they do not. Given how this has played out since last summer, I have no reason to believe Chase intends to fix this issue. I believe they will refuse to give me the title to the vehicle unless I pay the incorrect, higher amount.