Bad bad service

I bought a pair of shoes for my daughter Friday 13/3/2015 and when I got home the were a size too small for her. On Monday 16/03/2015 I went back to the same shop to exchange them however the slip was half as it was stapled outside the plastic packed and it was damaged ion the process. I spoke to a lady Mercy that tried to help me and she asked he manager and he/she just said no its wont be possible to help me.mercy put me though costumer service where I spoke to Mpho she said they cant help me .I am not stuck with a new pair of shoes that my child cant wear. What am I to do with these shoes