Product: Credit card

I received My my tax refund through XXXX XXXX serve card by American Express... and On XX/XX/XXXX I paid my phone bill with my serve card by American Express, The day before I had a balance of {$860.00}, after paying my cell phone bill I checked my balance through the serve app and it said I only had {$15.00} I check recent purchases and there wasn't any info as to why my money was gone... so account I called their customer service to get more information and on their side is showed that there was four withdraws made each being XXXX ... totaling up to XXXX that had been taken from my account from what they said it was out in LA .... I asked them how is that even possible I have the card, They asked me if I had given the pin to anyone I told them absolutely not there's no way somebody would have just guessed my PIN number and even if they would have they needed my card to pull out the money unless they generated their own .... I made a very clear that I don't share my information with anyone The only information I've shared was with them on their serve app in order from my refund to be deposited into the prepaid card through American Express .... I told them I didn't authorize anything and plus this all happened while I was at work and there's video of me at work ... their customer service representatives could barely speak XXXX, They were rude and no help, I was told that they were going to send me a declaration that I needed to fill out on my end for their investigation, and said could possibly take up to 45 days ... It's been about 15 days and I received an email telling me that they denied me for temporary refund of my funds the XXXX because I didn't qualify... I didn't understand this so again I called your customer service helpline and the lady on the phone said I was only denied {$200.00} that The investigation is still ongoing... I asked her why and she can please give me some more information and she said that that's all that she knows on her end.. I asked to speak to a supervisor someone who can give me a little bit more information she said she was more than qualified and refused to put a manager or supervisor on the phone, she just kept telling me the same thing over and over that I have to be patient that the investigation is still ongoing and it can take up to 45 days... 
She refused to tell me anymore, This money was taken for me and it seems like they are refusing to give me my money back ..... I never authorized anything I didn't even know that I was being robbed while I was at work... She said that they investigated but if they would have investigated or looked back on the video at the establishment where my money was withdrawn from You would be easily be able to see that it was not me who took that money out, she actually told me to call the ATM merchant to get more information I told her no that that was their job I thought they had investigated I just feel that I'm going in circles with the serve American Express... I looked at the reviews online more than XXXX negative reviews all stayed in the same thing that I'm going through I need help I'm a single mom that depends on her refund... 
Please help me get my money back. They are the only ones that have my information social email address phone number everything .... They will not help me. I thought because XXXX XXXX serve card by American Express would have secured my information .... No ... .they didn't and I was left with nothing!