Torga optical springs mall

I am shocked to my core i went to torga optical in springs mall. They provide me with a quotation of over 3000 to pay in after my medical aid contribution. I declined the quote On my way home i received a call and the lady advised that they can make changes which would leave me with an amount of 844 to pay in. I agreed after confirming the amount 3 times and advised that we would pick up the specs on the 20th which we did and made the required payment. I received a call today and was advised that i need to pay in an additional amount of over 600 . i am not happy with this turn of events