Twills Bypass road Parvathipuram - Not to return the difference amount

I bought inner wear for my daughter M sized sports bra , cost of Rs***, on *.may ****, bill no **.and another item of Rs *** and total bill ***.my wife asking same size with different colour, but shop keeper gave L size, shopkeeper said same size, but we did not watch at the time of delivery, Today *th may **** went to the shop and asking about the product, they are willing to change but did not have back money, i selected another item with the cost of Rs ***. He said to make another product worth the difference amount of Rs **. But I'm not agree, no usable item not there at that cost, i want to get Rs **. But he said he will not have right to gave money to the customer, i hurted. Why you not get back my difference money to me, he said we will allow to change the product but not to gave the difference amount of money, if you not take any product with the difference amount cost, you can left that amount to the shop. I leave the shop not collect the money, i lost my right to get the product by paying phone pe but while changing the product the store not given either cash or any online payment to me. Hence I request to the kind authorities solve my problem and justice to the public and no store owners not behaving like this to the customers. Thanking you. Yours faithfully, Ch.Kiran kumar, teacher,**********.