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

I feel I was cheated out of a full refund of my {$440.00} deposit for a tour I had charged to my Citibank XXXX XXXX XXXX XXXX Mastercard. I also feel the fault lies with XXXX Billing Disputes Department. It was a straightforward dispute. Summary : On XX/XX/XXXX, my travel companion and I each charged a {$440.00} deposit to our bank credit cards. The deposit was for an XXXX tour package offered by XXXX XXXX XXXX beginning XX/XX/XXXX. 
On XX/XX/XXXX, per media reports, XXXX XXXX XXXX ceased operations and all holidays departing on or after XX/XX/XXXX were canceled. 
On XX/XX/XXXX, I received in the mail a letter from the accounting firm XXXX XXXX saying XXXX XXXX went under Administration. XXXX XXXX recommended all US citizens submit a claim through their credit card company. That day, I opened dispute XXXX online with Citibank. My travel companion opened a dispute with her bank, XXXX XXXX XXXX, Visa. 
On XX/XX/XXXX, Citibank Billing Disputes Department asked for supporting documentation for proof of cancellation. On XX/XX/XXXX, I emailed them the XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX and the XXXX XXXX XXXX. Note : My travel companions bank requested proof of bankruptcy on XX/XX/XXXX. She emailed them the same documentation that I had sent Citibank, they found it valid and her conditional credit was promptly made permanent on XX/XX/XXXX. 
From XX/XX/XXXX until XX/XX/XXXX, I went back-and-forth with the Citibank Billing Disputes Department arguing with compelling evidence my case for a full refund. I felt the Citibank Billing Disputes Department mishandled the dispute and did not protect me under the law. To cut my losses and maintain my stellar credit, I eventually settled for a {$190.00} credit, 43 % of the charge. I then decided to open a complaint with the CFPB to look into this case, get better answers from Citibank and perhaps help consumers in the future.

<==============================================================> A full account of my miserable consumer experience can be found in the attached Timeline for Citibank Dispute XXXX and supporting exhibits. 
I hope to get a thoughtful response from Citibanknot a formulaic one like their automated letters or no response at all. 
<==============================================================> Questions for Citibank and Considerations for CFBP 1. Citibank : Why did you not believe the documentation I sent you proving XXXX XXXX was insolvent and could not possibly provide the tour but instead kept insisting that there was no proof of cancellation? 
2. Citibank : Who did you actually communicate withthe merchant or the merchants bank? I can not believe you communicated with XXXX XXXX because I could not reach them via phone or email. If you communicated with the merchants bank, what did they say? 
3. Citibank : Did you properly follow the Mastercard chargeback rules and procedures for " Travel services arranged through an online travel agency or tour operator that were not received and the travel agency or tour operator is no longer in business. "? Is so, when? I sent you all the supporting documentation for unprovided services on XX/XX/XXXX, three days before the tour was scheduled but never took place. If you did communicate with Mastercard, what did they say? Your last form letter to me said you no longer have any available means to assist you in this matter since the timeframe in which to resolve a dispute has passed. You were responsible for the delay.

4. Citibank : Why couldnt you reopen a conditional credit for a dispute for my account? The online Dispute section for my account said Conditional Credit Applied but it wasnt reflected in the accounts list of transactions. Very confusing.

5. CFPB : I thought I followed all the rules for opening a dispute for a service not provided by an out of business merchant. If I overlooked something, can consumer law and protections be further clarified, simplified and/or standardized for all bank/card network credit card purchases? Just as an example, when the airlines, especially United, were trying to force future travel credits/vouchers on customers when they cancelled flights during the pandemic, the DOT issued an XX/XX/XXXX Enforcement Notice and I was lucky enough to get airline refunds on another trip. The airlines get bailouts, the banks get bailouts/Federal Reserve loan backups, its a toss-up for the consumers : can get consumer-friendly support or get a hard time.

<============================================================> I wanted to say I have been a good Citibank customer for over 30 years with very few disputes. For all my loyalty, I felt like I have been slapped in the facewhat should have been a chargeback to the merchants bank ( since XXXX XXXX was insolvent ) and a refund in my favor was instead countered with evasiveness or perplexing replies ( How could Citibank say there was no proof of cancellation when the merchant was completely out of business? ), multiple phone calls and live chats, a partial credit and just lack of support and, what I feel, not protecting me under consumer law. This shows what a broken bureaucracy Citibank is when things dont go smoothly. My travel companion, a non-elite XXXX XXXX XXXXXXXX Visa credit card holder was refunded within two months. My niece who has had her XXXX Visa card for less than half the time I have had my Citibank card, got a XXXX XXXX refund from her bank when XXXX tried to force a significantly change flight schedule on her or accept a voucher. These banks know how to treat their customers. On Citibanks emails to me, at the bottom it says " Citi is at your side before, during and after every purchase. NOT! All I can say, if Citibank does not care for my business, then I will not give them any. I will not use the two credit cards I have with them, make them dead accounts and Citibank will be dead to me.