I'm not sure who to speak with about this...

I'm not sure who to speak with about this problem . I went online to purchase a product tonight and chose one of my credit cards to pay. It was rejected. So I tried the other card from the same company and it too was rejected. I contacted that company and was assured nothing was wrong with their end, that the company I was purchasing from must have had some wrong information on my account they were working with. I used my PayPal next and everything went through as normal. Are there some companies that are using some wrong information on my accounts and I need to get this straight? How do I find out who, how, where ,etc. Of this potential problem. Does Google maybe have dated information that is still in their system and is therefore rejecting the right info? Same thing with Facebook. How do I begin to try to find out what the problem is so by it can be corrected? Sharon
JA: I'll do all I can to help. Can you tell me more about what's going on?
Customer: I
Iwhen I attempt to purchase things online, my credit cards are rejected
JA: Is there anything else the Expert should know before I connect you? Rest assured that they'll be able to help you.
Customer: Not always. It's like there's a glock somewhere in my information. I contacted Discover about it and there is absolutely nothing wrong on there end.