Product: Bank account or service

This is in regards to a discrepancy with my account following the XX/XX/XXXX. On the XX/XX/XXXX I deposited a check made payable to me in an amount of {$10000.00}. Due to this large sum, I spoke with XXXX named, XXXX to confirm when the money would be deposited, which she replied as within XXXX business days. When XXXX gave me the official receipt for this transaction, I was at first mistakenly given an official receipt for {$1000.00}, which I noticed instantly and asked for a corrected second official receipt for the correct amount of {$10000.00}. The first incorrect official receipt was ripped up by XXXX, therefore I am only able to present the second official receipt. 
On the XXXX, I received a mailed reply from the US Bank XXXX Department regarding the issue, explaining that {$9000.00} was deposited into my account for the banking error, which XXXX deposited {$1000.00} only. Around this time, I was also informed by my colleague that the amount of {$9000.00} was still sitting in his checking account. 
Concerned, I went to the bank on XXXX and spoke with their employees ( XXXX, XXXX particular ) regarding the money that was still sitting in my colleague 's checking account ( XXXX ). They told me that everything was fine, that the money was properly transferred from XXXX. I continued to visit the bank every morning till the XXXX to inform the employees that the {$9000.00} was still sitting in my colleague 's account. XXXX and the other employees continued to explain that there was nothing to worry about. XXXX also explained that if I wanted confirmation of the check being cleared successfully, I needed to give her my colleague 's bank branch zip code and his last XXXX digits of social security - which I later provided. XXXX supposedly received confirmation by referring to the XXXX Department where she spoke with a woman named XXXX and provided a handwritten note which said the case was closed between XXXX, and also told me in her own words " do not bother me anymore about this case ''. 
On the XX/XX/XXXX, I also personally spoke with an agent named XXXX with US Bank, who explained that there was no problem regarding the {$9000.00} in my account. 
Finally, on the XX/XX/XXXX, I was shocked to find detailed in my transaction history ( XX/XX/XXXX in the transaction date ) that {$9000.00} had been withdrawn without my permission, without any notice, reason, or comment. When I went to the bank to complain about this issue, I was met with lax employees with unhelpful response to this dire situation. I 'm in absolute shock by this because the employees at my branch are claiming they are completely without fault. I spoke with XXXX, but he waived me off, saying that I should retrieve the {$9000.00} from my colleague. XXXX continued to explain to me that the {$9000.00} that was previously added to my account was given as bank credit. He then asked about my nationality and my culture and told me to stop talking in an aggressive manner. On XXXX, I also showed XXXX documents regarding the {$9000.00} which was still held in my colleague 's account from XXXX through XXXX but he said he could n't trust the documents. The delinquency of duty by the employees makes me question the entire operation managed by US Bank. If the remaining {$9000.00} was never transferred in the first place, why was I told that the funds were transferred successfully in my account? Why was I repeatedly given assurance that everything was fine? How can I trust other banks if a member of FDIC has failed me?