I think you should get these two different quotations (for a 10dollar letter) in writing from the two flight schools.
Photo copy these and take the photo copies to the head of the Jordanian CAA.
Ask him if this amount of money is what he has approved to be paid under his jurisdiction and if not how you should now proceed to be able to resit your already passed and fully paid for exam.
Hopefully he will !!!! all over these two flight schools...unless he owns them!