How long does it take the phone company to release a phone number to another person?

Is it possible for the phone company to accidentally give the phone number of an account in good standing to another person?

Can this even happen?

there are anti-slamming laws against that. to port a phone number from one provider to another, the customer (you) must give expressed consent either via a recorded third party company verification system (over the phone) or by signing a letter of authorization (actual piece of paper). if you find that your number has been transferred to another provider - seek assistance from your current provider. chances are they would never want to "mistakenly" lose a customer. they will assist you the best they can. the only time i can see anything like this happening is if the number originally belonged to the provider who it was snapped back to. if that happens, then your prior, original provider can be sued for it.