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

My credit card was charged by the vendor XXXX XXXX XXXX on XX/XX/XXXX for the amount of {$11000.00} for the purchase of an aquamarine center stone and diamond ring. The ring was advertised and valued at {$68000.00}. After engaging a reputable local appraiser, I discovered the ring was falsely advertised as an aquamarine and dimanond ring. It was in fact a topaz and diamond ring of a much lesser value ( approx. {$7900.00} ).  I engaged the seller who recognized the mistake, took the ring back and acknowledged to refund me the {$11000.00} on XX/XX/XXXX. As of today I did not received the refund. 

I opened a dispute with citicard on XX/XX/XXXX and provided very detailed documentation of the purchase ( 28 pages in total ), appraisals of the ring, confirmation of the return of the ring to XXXX XXXX XXXX  and email traffic between me and the seller, who acknowledged receiving the ring and to refund me the {$11000.00}. 

I called and chatted with the citicard dispute office in 3 occasions just to make sure they had everything they needed. The answer was always yes and that they would come back to me with a resolution. 

On XX/XX/XXXX, without any previous notice, I received an email from citicard that 2 of the 28 pages I've sent them were not readable and declined my dispute. The {$11000.00} were back on my credit card. I called citicard dispute office to verify my next step and after receiving instructions I resubmitted all the documentation again with a " more readable '' version of the two pages they were questioning about. I called and talked to two dispute specialists again who ensured me that all the pages now were readable and that another specialist would get back to me in a few days. The people I've interacted with so far don't seem to even read my emails or the documentation I've provided. One of them even told me that my documentation never made it to the seller financial institution. Between XX/XX/XXXX and XX/XX/XXXX nobody at citicard even looked at the details of my dispute. 

This should be an easier resolution considering I've returned the ring to the seller and I've the message from the seller acknowledging the ring was not a center stone aquamarine but a center stone topaz ring of a much lesser value. I even have provided the message from the seller who agrees to refund the {$11000.00}. I'm not confident in the ability of citicard to handle this issue properly. I've been a valued customer for more than 15 years and in those 15 years only two disputes for less than {$40.00}. I was not expecting such poor customer service. 

For additional clarification about this issue, see details below of the opening statement I've provided to Citicard ( additional documentation to support my claim can be provided as needed ) : I've purchased from XXXX XXXX XXXX, owner of XXXX XXXX XXXX, a ring that was sold and advertised as an aquamarine and diamond ring valued at {$68000.00} ( I have the XXXX   appraisal report that XXXX provided as documentation ). The ring was sold to me at {$11000.00}. 
When I received the ring, I had the impression that the center stone was a lot darker than the pictures XXXX XXXX send me and I decided to engage a reputable and certified XXXX appraiser to validate the authenticity of the ring ( XXXX appraisers are the only recognized appraiser service in the country ). When I initially purchase the ring the seller told me that the ring was coming with a XXXX appraisal, not an XXXX appraisal which is the one they  provided. I got nervous and decided to engage a local reputable appraiser. My appraiser documented that the ring was not an aquamarine, but a topaz of a much lesser value and some of the diamonds were questionable. His suggestion was to return the ring because he didnt think this was a reputable seller.The value of the ring based on my private appraisal was approximately {$7900.00} and assumed the diamonds were real, which he doubted strongly but some of them were so small he could not tell. 
After this discovery, I tried to contact the seller without success. The phone number was disconnected. I was able to reach by phone the XXXX appraiser the seller has engaged, who was shocked to hear what happened and ensured me the ring he has appraised was an aquamarine. He also told me he would contact the owner of XXXX XXXX and would make sure he would call me back. 
When I was finally able to talk to XXXX XXXX ( the owner of XXXX XXXX XXXX ) via phone, he said the ring was authentic and ensured me that my appraiser was mistaken. To prove my appraiser wrong, he agreed to do a XXXX appraisal himself, free of charge for me, just to show me that his XXXX appraisal he originally sent was accurate. He also agreed to refund the full {$11000.00} if the ring was in fact a topaz of much lesser value ( I have documentation of this ). I then sent the ring back and was received by XXXX XXXX it on XX/XX/XXXX. 
The XXXX report came back to XXXX XXXX and I got confirmation from him that my appraiser was right : the center stone was in fact a topaz and not an aquamarine. I asked for XXXX XXXX to honor his commitment to refund me the full amount of {$11000.00}. He was apologetic and said he would issue a credit immediately. Since then, not only XXXX XXXX has not returned my messages and calls, but the credit has not been issued, as hes committed to do. Not only he's the ring, but he has my money.