Product: Credit card or prepaid card

I have a debit Eppicard in Georgia thru Mastercard. I receive child support on this card from my kid 's dads. I rarely use this card as my husband and I use it as a savings account. I use it mostly for gas. One day I went to use the card and it was declined. I immediately made an account and saw that there were months worth of charges that were made to my account that were not mine. I still had my card with me so it had not been stolen. I filed a claim XX/XX/19 with the fraud services department for Eppicard. They sent me a questionnaire that I promptly filled out a returned and they started their investigation. After a little more than three weeks, they told me to fill an official police report which I did on XX/XX/19. The purchases for the account that were not mine spanned from XX/XX/19 - XX/XX/19. There were 92 transactions over this time and the total came up to {$4000.00}. After about another three weeks I received a letter from the fraud services department. That letter stated : " Based upon our review of the information you provided as well as our internal records and your card history, we can not confirm that fraud occurred. Our investigation indicates that you entered into an agreement with the merchant, and the transaction was processed in accordance with that agreement. '' I was shocked to hear this. I asked my husband to handle this because I was too emotional to do so and I have problems with anxiety. We do not have a lot of money and that money is basically our entire savings. They basically told us that we were lying about the charges. 

My husband called the fraud services department that very day and was on hold for more than 40 minutes. When we finally got on with someone their phone got disconnected. It was not ours as he has a cell phone and you can tell who dropped the call. We also have full service at our house. The next day the same thing happened in the morning. He called later that evening and finally got to the fraud services department. They reiterated the statement that was said in the letter after talking to many people for over an hour. He was also told that they could not fully reveal how they came to that conclusion. 

Furthermore they said they were not able to help because of a preauthorized settlement had taken place. This " settlement '' was not given by my husband or me and we believe that this settlement was done by the very person who stole the information from my card. If the person committing the fraud agrees to a settlement is that a real settlement? 

According to the letter they use the information I gave them, internal records, and my credit history to confirm that fraud occurred. I gave them all the information I had which was 100 % true. I have no idea what internal records is but I suppose since the amount was so much, internally they wanted to say no. If they used my card history they would see that this card, that I've had for over a decade, has never been used at the 13 merchants that it was used during this 3 month span. I have also never had that many transactions in such a short time or have I ever spent that much so quickly. I feel that they are deliberately and without reason not trying to help because of the amount of the claim. My husband even told them to come arrest us if they think this claim is false. We are at our wits end. 

I also notified them that two other cards of mine had fraudulent charges which made me reach out to them in the first place. The other card companies reached out to me because of the weird charges and did so pretty quickly. On one of the cards, I got a new card and had fraudulent charges immediately after getting a new card. I am not sure how this happened and have since frozen my entire credit thru XXXX and the other credit reporting services. 

Please help. Eppicard thru Mastercard is trying to renigg on their responsiblities