Yes, you are being unreasonable to expect a full refund.
Work got done, work should be paid.
One mistake was made, this does not invalidate the rest of the tune up.
If you had sustained actual injury, then yes it would be reasonable to have them compensate you for your injuries(tuneup fee being least of anyone's problem); but guess what? You got lucky and were not hurt, the shop got even luckier and did not have to go out of business after a long liability and injury lawsuit. Everyone came out of this alive. Congratulations and be grateful.
If you no longer have confidence in the shop, do not return in the future, that is all.