How long does Blockbuster keep account information on file?

I use to have an account with them, and racked up a few late fee's. However, my mom did the same thing, and went back and signed up for a new account just a few weeks ago, and they did not have her in the computer from before. Is there a certain time limit they keep non-active, money-owing accounts in the system?|||3 years but your information is forever like facebook