Refused to Exchange Dress

On the 6th February I bought 3 beautiful dresses at For Ever New access park,PURCH FOREVER NEW ACCESS P***, Description:*** 000000 S M ***60206Y.I only realize that 2 of dress, are too tight, Saturday (13/02/2016) i wasn't in Cape town, when i came back i went to store on the 20/02/2016 to do exchange, i told one of the lady assisting that i bought 3 dresses here, but 3 are too tight and i want to exchange, but i lost my receipt but i do have the transactions slip that shows the Shop name, amount, and reference umber and bar-code of the dresses bought. the 2 dresses still have the price.1st question she asked was, are you sure you bought this dress here? question no 2:are you sure we have this kind of dresses here? and when was it bought? again ask did you buy is here? and she said that her Manager wasn't around, so i must leave my details and they will contact me, after that she just took a small paper & wrote an email address and asked me to send a email to her manager to tell her that i want to exchange but don't have the original receipt and refused to take my details. i don't know what to do with these dress now & want to exchange them