Complaint sub-issue: Card was charged for something you did not purchase with the card

I am writing to you to express my concern with the way a fraud case is being handled by Home Depot. 
A couple of years ago, Home Depot sent me a store credit card which, as it was unwanted, was shredded, I do not ever recall activating or using it. I did not close the account but given my experience since late XX/XX/XXXX, I doubt if anything would have changed the course of events. 
I continued using Home Depot, XXXX Branch as one of my two main go to stores for hardware in the district. I always paid on my XXXX Debit Card or, occasionally, my XXXX Credit Card. 
No more was heard of the card account until I received a call from the Home Depot fraud department on XX/XX/XXXX. I was in XXXX and walking around a store with my wife when I received the call, the gentleman got right down to business and asked me about some purchases I had made in a Home Depot in XXXX, Texas that same morning. I informed him that it was not me and when he asked for further details I was happy to inform him that I had flown over XXXX just a few hours earlier on my way home from XXXX, XXXX. We talked a little more where he advised that my card account appeared to be reactivated and in use. He advised me to check my credit scores and open accounts. He concluded by telling me not to worry, it was an obvious fraud, ( please recall that he called me ) the account would be closed and would be investigated. 
Upon returning from the store I did as he advised and, as I had been out of State, I also checked my previous three weeks mail. Apart from the debit in question on my Home Depot account, I also had letters from accounts I was supposedly opening. Over the next few days the situation deteriorated as I continued to receive letters confirming card applications, questionnaires to fill in, etc. In addition, the credit score companies were starting to reflect all the queries for credit to the detriment of my excellent credit score. I spent my XXXX to XXXX XXXX break writing letters, cleaning up my credit scores and freezing my credit score accounts. 
It did not stop there, in early XXXX I received a call from the Exxon/Mobil credit card asking if I was having problems at a service station. I advised the person that I had been subjected to identity theft and he in turn advised that a person had been pumping gas in XXXX, XXXX and XXXX. I questioned how the person received a card when I lived at the address of record. He advised it was an interim downloadable Application and that the access had been granted before the freezing of my credit score accounts. I had another letter after that from another credit company asking me to unfreeze my accounts, so they could process my credit application, of course that was not me either. 
Now, that is the background, lets discuss Home Depot. During the last few months I have seen some strange movements with the so-called closed account. On XX/XX/XXXX, during the first phone call, I believe the amount on the card was under eighty dollars. I did not worry until it shot up to about three hundred and eighty dollars ( not sure on the exact numbers at this time ). I did the rounds, phoned the Home Depot fraud department, spoke to other people on line, the assistant manager at XXXX store, etc. All told me not to worry, the account was shown as closed and was under investigation. The following two months saw bills with a new twist, a XXXX   credit! I phoned and asked how a closed account could suddenly have a credit? I told the people on the other side of the phone line to do what they wanted with the credit, it was not my money, close the account and stop sending bills. Imagine my surprise this last weekend when I returned home again ( from XXXX ) to find yet another bill, this time for XXXX XXXX, XXXX XXXX and XXXX dollars, XXXX XXXX ( {$1800.00} )! Obviously, purchases were still being permitted after XX/XX/XXXX. I did the rounds again when finally, one lady told me that the fraud investigation had completed, and the charges were deemed genuine. I was astounded, an investigation was completed where I, a complainant in the case, was never interviewed, sent a questionnaire or even advised of the investigation outcome. 
The lady told me that she was placing the case back under fraud investigation. From my perspective this is an inside job at the Home Depot, XXXX Branch. The unused account has been hacked for my personal data. From a Home Depot perspective, I suppose it appears a strange kind of spending spree, whoever it was did not go straight out and buy the store ( but did manage to trip an internal fraud alarm in XXXX ). However, the larger picture shows a person utilizing my personal data mined from the Home Depot system to open multiple credit accounts and shows a much more illegal and sinister intent, that of identity theft. Note that nothing untoward preceded the Home Depot purchases on the unused account, all other attempts have been to open new credit accounts, therefore Home Depot, XXXX Branch, is the breech. I would have expected the company fraud department to take this breech of their card system seriously. 
Events have moved on. On Sunday XX/XX/XXXX I received a phone call from Citi Bank asking for a payment on this bill. I advised it was under dispute and they passed me to the Home Depot Fraud Department. A gentleman told me it was Sunday, so I would receive a call the next day, I never. 
On XX/XX/XXXX I received another call to collect a payment on the card from Citi Bank. I was in work and a bad location for lines dropping and after a brief conversation where the operator told me the matter was still listed as a valid purchase and not a fraud, the line dropped as she was passing me to the Home Depot Fraud Department yet again.