If you keep the invoice of the lube and filter job you had done from outside, then simply get them to contact the lube supplier
Meaning,
If they say that mobil1 is garbage product and destroys engines, get this in writing from them (kia dealership) under letterhead and signature, send it to mobil askari and exxon-mobil support in usa.
Keep yourself involved in it, and you may earn a lot of money from this. Ive done it, it was awesome and it was in Pakistan in 2001. It was a lube product on an industrial constant speed transmission.