Terrible help desk

I've been trying to get my card machine to work after 2 years of no use. Last Friday I was told confidently to use the machine over the weekend by their help desk person. I did this and they consequently paid the money I took into a closed account and tell me to deregister the machine and reregister it on a new profile but refuse to answer any questions about the money. I used to believe them a reputable company and mistakenly recommended them to several colleagues and friends. I feel quite embarrassed