Handed over to debts collectors

I work for a company called Gilbarco AFS. During the month of June, the company had a wellness day for their employees, Pranesha pillay optom discovery (company) were invited. Then I did the check up for my eyes which they told me that i have problem with my eyes, special at night.<br> And told me that i need to get Glasses which I agreed to buy it and i choosed the type of frame that I liked and it will cost about R2360 . we had agreement of payment that they will debt about R361.00 for six month which I give them my banking details and they said that they will first debt the money before i can get the Glasses. Just before the end of the month they send me an SMS with their banking details saying that they will no longer debt the money i need to send them the money on their banking details. This was not our agreement at first and there is nothing wrong with my banking details which they chooses to change on what we agreed off,and now they have handed me to debts collectors for the money of Glasses which i don't OWN IT and also the money has increased to R3552.19. Can I please get helped on this matter because they are ruining my name to send me to debts collectors. <br> <br> thanks