What if the stimulus check got sent to an account that I now longer have?

Once the bank bounces back your stimulus check to the IRS, you will be automatically switched to receiving a check in the mail.  It can take 4 to 6 weeks to receive the check. 

https://www.irs.gov/newsroom/treasury-and-irs-begin-delivering-second-round-of-economic-impact-payments-to-millions-of-americans