This is the exact same thing happening to me and it seems to be Brazilians (based on the names, emails sometimes ending in .br and sometimes the bank that declines the card is located in Brazil). Has been happening for months beginning only this year...

What about in my case where the email differs and the address is always the same except for the state, its always a different state?

Today I had one of their attempts to actually go through after months and months of them trying. What does this mean for my site? 

One of those many attempts on my store was actually successful today. The order went through and now I am not sure what to do. Have been able to fix the problem?