USA/EU Departmental Store Sweepstake Lottery, Metro Financial Service, Southern Management Corporation you have won $50,000 Dallas Texas

I received a letter in the mail stating I had won 2nd place, winning the sum of $50000. It had a check for $4000 included with the letter. Instructions was to call and activate the check so taxes and delivery fee can be paid and with doing so the remaining $46000 will be delivered to me by UPS which is who I would pay money to. I was under the impression that this was to good to be true but I contacted Thompson Grey as instructed @9406028072 where he took a number on the letter and called me back, which I did not provide a number but figured he had caller id. After he returned a call, I was instructed the check was now activated and was to cash it and call him back so arrangements could be made for other check. This just seems like a scam, I have been part of a scam in the past and was wondering about this as well.