Dunnes Stores complaint: Communion dress

I purchased a Communion dress and bolero in Dunnes Stores Blanchardstown in February 2020. The communion was cancelled due to Covid and was not re-scheduled until September. I tried to return the dress to Dunnes in Blanchardstown but i was informed by the manager that I could only exchange ‘like for like’ the issue I had with this is there was no Communion stock I could exchange that would fit my daughter. She is very tall and all of the stock left was for aged 5-6 which wouldnt fit her when she was 5 years old. I asked the manager to even give me a credit note and she refused because the dress could not be sold on if Dunnes took it back, a bit confused by this because if I was exchanging like for like they would have taken it back and then sold it on? I had to purchase another full outift from another store and I asked the manager again to consider a credit note and explained the situation again and she advised me to sell the dress online. I understand the 28 day policy of return but given the pandemic I had hoped for a goodwill gesture from Dunnes Stores and I would have happily taken a voucher to put towards shopping.