ARCO review: manager kept money I left for gas payment during emergency

On 1/15/2019, around 12:30 or 1 am I went to the Arco gas station and left around a little over 4 dollars in coin at the register and with the attendant. I then stepped aside to get gum. During this time a man who knew the attendant was in the store and was holding a gun. The attendant, a female kept telling the man, "put that away" and addressed him by name. I returned to line and realized at that time it was a handgun the man was holding. I was frightened by this and told the attendant, "I'll be back". I rushed out of the store and called 911 to report this.
I then called the attendant at the Arco and asked if she was ok, and explained I called 911 and left money at the counter. She told me she was ok and she knew the man, and told me she had my change and that I could come back any time and get the gas I paid for with the change. I told her it would be some time later before I would be in the area for gas but she reassured me the money was set aside with my name (I gave her my name).

I have been unable to collect the money or the gas since. I have made numerous attempts. The manager Melody (Melanie) today hung up on me insisting I made the whole thing up and told me to call corporate. She has since ignored my calls. Please help.