Complaint sub-issue: Debt is not mine

Unresolved Citibank issue ( {$250.00} ) XXXX XXXX, XXXX {$23.00} was the original amount for an administration fee ( everything else is late fees imposed by Citibank ). 
This was a government issued credit card that was used for official traveling purposes only. 
The training class that I was attending ended a day early so I did the right thing and changed my flight to an earlier one. Upon return, I filed a timely expense report, as required. There was an additional amount charged of {$150.00} and a CTO fee of {$5.00} ( original fare was {$340.00} ). These were all the charges. I have all records. There was no other administration fee at the time I filed my expense report that I was made aware of. If there was I would have included it, obviously. I only became aware of it after I was terminated from this job when I received a letter from Citibank. ( If I was still working there it would 've been an easy thing to amend. ) I immediately contacted my employer. I was told that I did not owe it and they would take care of it. 

XXXX XXXX Received first letter from Citibank for {$23.00} ( this is when I first became aware of the charge ) Called employer ( XXXX ). XXXX left me a voice message on XXXX XXXX stating that I did n't owe anything ( I have the voice message ). He forwarded emails stating this to XXXX several times. I also called XXXX several times and left several messages. I never heard anything back from him. 

XXXX XXXX XX/XX/XXXX called and left messages for XXXX, XXXX and XXXX ( heard nothing back ) XX/XX/XXXX called and left messages for XXXX, XXXX and XXXX again ( heard nothing back again ), Also called and left messages for XXXX and XXXX, XXXX name given to me from Citibank. ( heard nothing back from anybody ) XXXX XXXX XX/XX/XXXX called and left messages for XXXX, XXXX, XXXX, XXXX and XXXX XX/XX/XXXX talked with XXXX and XXXX. XXXX said he was going to look into it. XXXX was not helpful. 
XX/XX/XXXX called and left messages to the same XXXX people. 
XX/XX/XXXX XXXX finally got back to me. She said HR ( XXXX ) is refusing to pay it. 
XX/XX/XXXX talked with XXXX again. 
XX/XX/XXXX called and left messages for XXXX, XXXX and XXXX. XXXX returned my call and left me a message stating that they are working to get it resolved ( I have the voice message ). 
XX/XX/XXXX talked with XXXX again. Left messages for XXXX and XXXX. XXXX returned my call and said it should have been paid in the beginning. She said it will be paid by the beginning of the following week but not the late fees! Nothing has ever been paid! 

All along I continued to make calls to Citibank with no luck. I ask for a manager to call me back and he was completely dismissive. He was unwilling to do anything and refused to talk with me. 

XXXX XXXX Citibank has now sent this to a collection agency ( XXXX XXXX XXXX ). 
XX/XX/XXXX called XXXX Services twice. XXXX with XXXX. He filed that I 'm disputing it and forwarded it back to Citibank. He said it should be there by Thursday. Also called Citibank twice. XXXX with XXXX and XXXX. They said they could not do anything until they get it back. 
XX/XX/XXXX called Citibank again. XXXX with XXXX who was no help and said they are not able to do anything with government cards! She refused to forward my call to a supervisor. She continued to refer me back to XXXX Services even though I repeated several times that they sent it back to them. Citibank has refused to work with me since day one! They have harassed me continuously with XXXX voice messages! 

I have done all I can to resolve this matter and have been unable to do so. I have spent hours on the phone alone. It has affected my health over the last several months as well. 

This was a legitimate business expense and I expected the government to pay all along. 

I had spotless credit before this and insist that it be rectified immediately. Thank you for your attention to this matter.