Amazon.com.kydc.inc Jessica Brown sent cashiers check for less than posted price, no ship to address Alexandria, Va., Seattle,Wa., Detroit, Mi. Nationwide

I listed an electric wheelchair on Austin,Tx. Craigslist, along with a lift for the rear of the vehicle. Listed price for $2000. Had text messages from at least 2 people with the same name but different phone numbers with different cities/states. Recieved a chashiers check for $1700. from a Detroit, Mi bank. remitter, Jessica Brown. It was delivered to an address that is ONLY listed on my Amazon Prime account.

The Fed-Ex envelope said:  Amazon.com.kydc.inc.  535 Terry Ave, Seattle Wa. The check, from a Detroit bank.

When I looked up the tracking number, it was sent from Alexandria, Va. No return address, no ship to . Nothing but the check in the envelope. First,how did they get the address??? Second,why was the check $300.00 ahort, if it was for my craigslist item?? Third, if not for my item, why send a check??