Refusal to exchange gift

I took a dress that was given as a gift for my 5 year old daughter to Truworths at Centurion Mall on 28th November 2020. We do not have an account with Truworths and we are not aware of exchange policy. We got the gift in Feb 2020. Then lockdown happened and we did not get a chance to exchange it. We only just started going back to the mall in past three weeks. So we decided to finally change the dress as it does not fit my daughter the size is incorrect. I was even prepared to pay the difference if I took something more expensive. The people at the till refused to take it back even though It had the gift receipt with the original receipt and barcode. I am very disappointed at the kind of service and the utter refusal to assist me even though I was will to pay the difference for something more expensive. The dress was only R199. I am not asking for refund but a mere exchange for the goods. They should be more understanding as we all still getting over lockdown and this pandemic.