POOR SERVIVE

I bought a Tshirt in November and I took it back today cause it doesn't fit my daughter so I decided to take it back, I walk into the store and the 2 staff members are talking I was standing and waiting for one of them to assist me so when the conversation was done they assisted me, he looked at the slip and told me he's not returning it cause it pass my return date...he had such a bad attitude and I did have proof of purchase swing tick is on so I don't understand what the problem is according to consumer act returns have 6 months he refuse to help...there was no supervisor or manager and he refused to give the managers name and said I can come back when the manager is there...how do u open a store without management??????it's so disappointing cause he did not even try to assist me and this type of behavior is unacceptable!!! How do a shop assistant make that type of call not even trying to call management!!!!