Front end realignment after getting motor replaced

I had to have my motor replaced on my 2012 kia Optima
under warranty. My tires were 7/10 in the front when it was
done. Then 6,000 miles later , both outer edges were
completely warn out. Since they replaced the motor by
dropping the entire front end out of the car , upon replacing
it I believe the alignment was thrown out. The dealership
denies responsibility and says it was my own fault.