Manager refused to do an exchange for me.

God day on the 10 of April I bought 3 leggings didn't fit them then when I got home I found out that they a big on the 12 when to exchange but the manager refused to do an exchange for me she forced me saying I wore the leggings which I didn't she said I must take my airtime call the call centre log a complain to say I bought damaged leggings and get a reference number then she will exchange and that she can't call and report my leggings as damaged. They where still in the price tag and she said I wore them because they had friction between thighs I explained that I couldn't wore them since they were big she was rude to me and left me on the till without reaching an agreement saying am taking chances.