Can a business change the price of products after purchase is done two weeks ago?

Bought 4 boxes of contact lenses from my doctor’s office two weeks ago. At time of purchase, I was given a price of $93.00 per box, I agreed to it and paid in full. Received a receipt for my payment. Now two weeks later I received a call that they want to charge me additional $224.00 because the employee made a mistake of giving me the incorrect price. I refused to pay additional charges and offered to return the product, but they refused the return. Am I obligated legally to pay the additional charge ? What happens if I do not pay the additional charge? I am in Houston TX