Paying for Prescription Sunglasses I didnt approve

I had a horrible and unprofessional experience (from Receptionist) at Execuspecs Woodmead. I already wear spectacles and had been there a year prior for the spectacles I currently wear. I tried on a few pairs of sunnies in September last year, there was a pair I liked. She said she can SEE how much Medical Aid (Discovery) WOULD approve. (Meaning she will be CHECKING). I tried to use my medical aid a month later and was told that I had no funds. I realised that I had no funds because it had pay out for sunglasses at WOODMEAD that I had not approved. now get SMSes that my account there is overdue and need to pay. This morning I get a call that my account will be handed over to legal team as I have failed to pay . I dont understand how a verbal conversation of her checking how much medical aid would pay results in me having accepted to purchase the sunglasses.