"Even if you 'resign', they still have your data."
Before you leave, poison your data.
Before you leave, poison your data.
"When you update information, we usually keep a backup copy of the prior version for a reasonable period of time to enable reversion to the prior version of that information."
They could assume that any changes made to data just prior to canceling an account are suspect. So wait. Or don't ever cancel, just stop using the service.