Paid and still handed over for collection

Eye test on the 31.05.2014 received my glasses a week later which would be around 4.6.14. Glasses were not correct they were to strong. I contacted Glenda at Spec savers and she said i was to come back in. Due to my relocation to Johannesburg I was unable to go back in. As this account was on King Recruitment's name they got hold of me and I started paying the amount of R200.00 a month. Payments made on 29 Oct, 5 Nov, 25 Nov this was a December payment and then last payment on the 26th Jan - Total R800.00. Reading the Invoice said Industry Total R694.00 and Patient Amount Due R429.00 now tell me what amount is correct and then in December Spec Savers handed me over. I find this totally unacceptable and now the Debt collections wants me to pay them nearly R500.00 for them having to collect money which they didn't have to do as i paid the full amount and by looks of the invoice i have to much. I feel that Spec Savers needs to give me back my money that I have paid and I will return the glasses that I haven't used because of incorrect lenses. Spec savers to pay Debt collections. I sent thru my payments to Sandra at *** with my email address and nothing was done.