Product: Credit card

I apologize for the lack of dates. Today 's date is XX/XX/2023 what has transpired has been within the last 30 days. I can not log into my capital one app even after downloading it again as directed. I find this highly suspect. 
I am writing this letter to inform you of a grave mistake that was done to my credit by my credit card company. Personally, I am.still amazed that I am made to fix the issue alone when Capital One has already admitted they made a mistake. Making this an internal matter to fix. If the situation involved a XXXX party company they would be all over it helping as much as they could. To the matter at hand. 
A concert ticket was purchased from XXXX with good intentions. I didn't I authorize it and contacted XXXX and asked for reimbursement. They agreed and sent an official email confirming it. Playing safe I contacted capital one to inform them of the situation. I was told to wait and see what they do. If by Monday they have not reversed the pending charge then they would instruct me to file a dispute. 
Come Monday this what Capital One and I did first thing in the morning. 
Not long afterwards the reimbursement {$100.00} arrived to my account from XXXX. I informed Capital One and went about my trip with my partner. At some point XXXX XXXX not paying attention as they say they do with all their XXXX  advertising ignored the fact the dispute had been resolved.. and sent {$97.00} to my account. No notification came to me concerning the deposit. 
Instead of removing the mistake right away, and trying to blame XXXX for the error and protocol.. they waited 8 days before removing the amount. I requested the reimbursement because the {$100.00} was going towards XXXX tickets for a XXXX show. Which I purchased. Leaving minimal funds on my card that I frequently paid off my balance weekly. 
Currently due to their error and lack of concern towards their clients credit score, which that specific card is designed to help improve. They removed the funds they shouldn't have given overdrafts my card. 
My credit score went from almost XXXX down to XXXX. Canceling my application to an apartment I was waiting for. 
Asking for them to rectify the situation. They told me to write this letter to their very own credit repair department. Which will take all together 30+ days. I was shocked that he wanted to sit their and read this to me after he verified on a recorded line that that paid me after the reimbursement arrived on my account. Informing me that they have no way of knowing the funds were returned??? 
I never heard a more straight forward lie in my life. That is precisely their job. 
I am requesting my credit score is returned to its original state before this debacle, and they charge wiped off my account since it cost me far more than the funds they mistakenly gave. 

I also received a notification of a XXXX XXXX  XXXX  purchase today XX/XX/2023 that I did not make. 
" XXXX XXXX XXXXXXXX Make a payment to help avoid future declines. 
Hi there, Your {$6.00} purchase at XXXX XXXX XXXX on XXXX XXXX was declined because you were already over your {$600.00} credit limit. 
If you make a payment now, it often will be reflected in your account immediately, but can sometimes take 1-2 days. 
Balance summary Credit limit {$600.00} Current balance and pending charges {$680.00} Note : We dont charge overlimit fees. '' How the he'll does this company operates in such fashion boasting the desire to help build your credit and when they make a massive mistake tell you to fix it yourself ... and then allows erroneous payments to go through no notification all while they are aware of the dispute.. 
XXXX.