Parkside Kia

I purchased a new 2015 Kia Optima in October 2015 for a little more than $21k. It is currently in pristine condition with a little over 16k miles on it. I like it. Gets good gas mileage. Nice, for a 4 cylinder decent car. I received a letter in the mail yesterday with what looks to be a hand-written (but its not) letter from General Sales Manager Frank McMillan. I read the letter, thinking it was sincere in wanting my car back since his pre-owned inventory is low. I read further and saw there was a 'check' enclosed. The amount of said 'check' is $13,020. Now, I'm not in the market to sell my car. It's practically new. But...that number struck me very hard. If this car has depreciated $8k in 15 months, I have made a dire mistake in my purchase. Really? The dealership. Offering me $8K less than what I paid. That is a terribly bad testament to the quality of this vehicle if that, in fact, is the case. How insulting! To beat it all, after purchasing mine, my son and his mother went to Georgia and purchased another, slightly older, 2013 Optima in January 2016. Now, I have TWO of these worthless things. Great. Thanks. Good luck fixing this.