Complaint sub-issue: Credit card company isn't resolving a dispute about a purchase on your statement

Here is the backstory : Upon the realization that due to COVID 19, I would be confined to my home for the foreseeable future, I asked my landscaper for a quote to improve the aesthetics of my property. I explained that my ex husband had been laid off due to the pandemic and that I would only be able to afford {$8000.00} of work. I could pay him {$2500.00} cash and the rest on a credit card. There was NO signed work order and I was never presented with a formal quote. I told him my MAXIMUM budget was {$8000.00} and that I would be using my tax refund and stimulus check to pay for the work. 

The work was performed on Sunday, XX/XX/XXXX. On Monday, XX/XX/XXXX, Mr. XXXX showed up at my home, said he went a little bit over and presented me with an invoice ( attached ) for the OUTRAGEOUS amount of {$14000.00}. I was absolutely sick over this. I wondered if there had been some sort of misunderstanding, had I heard him incorrectly, how could this have happened? I told him that was insane. He said if you dont like the work, Ill rip everything out. I felt threatened and uncomfortable. I am a single mother and my XXXX year old daughter was home at the time due to the pandemic. I gave him the {$2500.00} cash that day and he said we would work it out. Mr. XXXX came to my house every few days asking about the money. I was embarrassed and blamed myself. I was too scared to stand up to him, particularly with my daughter at home. 

They charged {$10000.00} to my Citibank Mastercard that they had on file for weekly lawn maintenance and continued to send me bills. If you count the {$2500.00} I paid in cash, this card should only have been charged {$5500.00}. I realize there is probably nothing Citi could do to help me recover that lost cash but I have been overcharged {$4700.00} in reality. However, I requested the disputed amount be {$2700.00} and cover only what I paid on the credit card vs the agreed amount of {$8000.00}. 

XXXX XXXX  was unable to provide anyone with a signed work order because I NEVER agreed to this price. There never was a contract, they dont have my signature on anything!!!!! When I speak with their accounting department, they try to appease me by taking some money off of the astronomical bills they continue to send, which is ridiculous. 

I filed a complaint with Citibank XX/XX/2020 after numerous attempts to unsuccessfully resolve with the merchant directly. They mislabeled the first dispute " goods not received '' instead of " incorrect amount ''. The dispute was forced to be closed and my conditional credit was reversed. A second dispute was opened. I have sent them emails between myself and the merchant where she admits there was NO written contract and I only agreed to {$8000.00}. They keep closing the dispute, saying that its my fault for ever giving the landscaper my credit card number for weekly lawn maintenance and telling me there is nothing they can do. They also keep asking me for a credit card receipt or a sales slip showing I was billed or charged the wrong amount. THIS IS THE ISSUE. THERE IS NO CONTRACT THERE IS NO SALES SLIP. The card was not run in my presence and I was NOT GIVEN A RECEIPT.