[Fagottino89]

Wasn't familiar with any of these methods up until today when accidentally doing some research. Originally had a guy that said he could get a refund for me but whatever he did didn't go through. From my super basic understanding it looks like he was using the FTID method since I got an email from the vendor saying that they contacted UPS and they responded:

"this package was delivered to your customer and accepted on ..... 5 days later they tried to return it but were refused a return, probably due to not including the correct information or product. So, from my understanding after speaking with our internal team your customer did receive the package/product and then after 5 days attempted to return without including the product. Which is why there is a 1lb label on it with no product inside of it.".

They also said that their opening up an investigation. What usually comes out of this?

Thanks,

Well depeds on the carier and what was done by the refunder. If he boxed them, he can try to say that the item was stolen on the way, which is the way boxing works.
If it is FTID and they're opening an investigaion, you have low chances of succeeding because the investigaion will most likely show that the box was never delivered to their warehouse