Long story short, a while ago, I bought and returned a hard drive that still had sensitive information on it including SOCIAL security number, passwords to online accounts, etc. At the time, I thought that I removed all the information on the hard drive because I quick formatted it a few times in a row just to be sure. However I just became aware that quick formatting is not the same as true formatting, wiping, degaussing, or sanitizing. My information is on there and its been messing up my entire life. I've been constantly stressing about it, and even losing sleep. I tried to go back to the store and see if they still had it but they said it was already sent back to the manufacturer to be refurbished and resold. I told them why I needed it and they said not to worry because they “remove all the data” before reselling it. I’m not sure what that means exactly, but I’m afraid they would only do a quick format just as I did. Now as far as I’m concerned I only have 3 hopes left of my information being safely destroyed, and they are as follows:

1.The manufacturer actually does perform a full sanitization of the hard drive before reselling it.

2. the next person who gets it sanitizes it themselves

3. the person who gets it next puts so much information on there, that it overwrites the data I have on there (I had a complete disk image on there).

That being said, are there any possibilities that I am missing? Is there any more hope for this dire situation? Please tell me something to comfort me!!!!
There is a good chance an attacker could recover that information. Though, it DEPENDS on the manufacturer's process. They aren't going to "quick format" drives- it's unlikely the drives get connected to a PC or computer for whatever tasks are performed, though I imagine part of refurbishing a drive would include wiping the drive, if nothing else than for liability reasons.

The better question shouldn't be whether a motivated individual *can* but whether the drive would ever come into the hands of somebody who can and is motivated to do so- which seems very unlikely. Somehow through refurbishment the data is left INTACT, the person who purchases a hard drive decides they aren't going to use it and instead runs a partition RECOVERY tool for some unknown reason, and recovers the original partitions, then pores over the recovered data to look for the private information that was on the drive.

I'd say the chances of that are incredibly remote.
Thank you so much for your reply BC_programmer!! I already feel so much better and I somewhat have a piece of mind now . Although I would still like to get more opinions on this, so please don't be afraid to chime in anyone.  You should use dban here. It will wipe it.
Too late...superdave, it was already supposedly sent back to the manufacturer. do you have any knowledge  on the subject?