Utterly disgusting service and robbing!!

I am utterly disgusted by the service of your reception. On 26 April I bought a few things. For some reason the payment kept "declining" as I was paying with my card. The one lady told me I probably don't have money in my bank account and I need to make sure that I have money. Who gives her the right to talk to a client like that?? She doesn't even know who I am and what I do. I come to your shop all the time and I was so shocked by the service received. On top of that, I left to get some cash and came back to pay. Last night when I checked my bank statement, the payment did indeed go off my bank account, so I was charged double. So how could they tell me my payment was unsuccessful if it was not? I have now paid double for my purchase and need my money back asap please.