Tiger Salamanders reach sexual maturity at 4-5 years old (according to pededucation.com). So the Tiger would be passed its larval stage, and therefor would not be breeding with an Axolotl. The odds of your Tiger Salamander remaining in larval form is unlikely, so you should expect to be caring for a Tiger Salamander someday. It may be intentional that this "breeder" is falsely selling axolotls because they are usually in high demand...or it may be completely by mistake. I would certainly ask him about it, but don't be too confrontational about it.