Left Sunglasses behind, never got them back

I was at the Nandos in Sandton City at around 14h00 on Sunday the 8th of March. When I got home I realised that I had left my sunglasses there by mistake, I understand that this is my fault. However, I called to find out if they had been found, the first lady I spoke to told me that they were there. I spoke to a second lady to ask if I could fetch them the next day and suddenly the sunglasses were no longer there, the lady I spoke to was being quite evasive. <br> <br> I called back and asked to speak to the manager, he said he would enquire and get back to me (he took down my contact details). I waited for him to return by call to no avail, two days later I called back and asked him for an update. He then told me that nobody had found the sunglasses and that there was nothing he could do. I asked him what process I should follow to which he responded again that there is nothing that I could do and that essentially it was my fault. <br> <br> I know that I should not have forgotten my sunglasses there, however I do expect some honesty from a retailer and its employees. I know that I left the sunglasses in the Nandos as it was the only place in Sandton City that I went to on the day.