Bad service

On Saturday 27 June I did my shopping with my husband and son which I always do every month, my son saw a transformer toy and what'd it we bought it & took it home to our surprise the was broken and we took it back the following day to exchange I told the lady its either u give my money back or I exchange it for another one, however she said she put it back on my card which I paid with, to my knowledge a cheque card is cash anyways she put the money back on my card and than tells me afterwards the money will only reflect in 2 days which today have still not shown I asked to speak to a Manager which she called Sbu and she already discussed with him our complaint, he was not helpful or friendly either and said there was nothing they can do,I said I am going to take another transformer toy as I promised it to my son but before I take it I will open it to see if its working,to our surprise he sent 2 security guards behind us if we opened the box to escort us out, we do our shopping there every month for over 2700 to 3500 a month and this is how we get treated, I opened the toy anyway and did care at this time because I was fusing and the toy was not working either,Not a happy customer