[stomachmonkey]

Kill the cards. Get replacements.

Religiously shred your confidential trash.

Is your wifi access point secure? Did you go into the router and replace the default admin login?

If not it's pretty simple to sit outside your house with a laptop and packet sniffer which can log unencrypted traffic as clear text.

I use one card for online stuff. One for day to day and another for big ticket purchases so if compromised I know where the breach came from.