Reformat your computer, You either have a keylogger on your computer or a remote access tool, they obviously are watching you, and your email/accounts, deleting the information prior to you receiving it so you do not dispute and or cancel your card.
 
Ever time i use paypal i remove my bank and or creditcard info right after i buy something and re-enter it at a later date again, but from the looks of it you have someone watching you and your accounts.
 
If you have entered your bank and or credit info on your computer lately, cut your card and get a new one. Someone has full access to your information.
 
You could of received this from purchasing software online, downloading software from people, or even going to an infected site,  with a java script exploit and or flash exploit .  One little program defect can cause hackers to gain full access to trusted software, and in turn they can put access or keylog tools onto your computer, with frequent updates.
 
I would also ask paypal for the IP addresses logged into your account, and also phone your internet service provider, for any suspicious incoming connections to your computer, most likely the hacker will use a proxy or several, making it very hard to trace and or catch him... but its worth a try to find the culprit.  If you like you can open Run> cmd  and type netstat -a , to see foreign incoming connections to your computer, anything suspicious you can write down. Call the dating site, and ask them for the account or user name and email that you are singed up under, and tell him to check into it as well.
 
Just based on the mail thing you told me i know this is the case, he was logged into your hotmail, and deleted the emails before you could read them. 
 
Reformat first, get new cards and then change all your passwords, it may be an inconvenience, but if hes an **** he will pull another one on you.  Judging from the dating site, hes probably a kid messing around on a dating site for free due to your information or... its a company that illegally pays people to sign up, and they keep the funds, i have heard this story with AV companies paying people to make Viruses as well.
 
Glad pay pal resolved the money, but you still need to protect your self, just encase.