Zara unreasonable offering me no return, exchange or refund as slightly over 30 days

Bought jacket on sale for R799 on 17 July 2018. Have receipt. Went overseas and my family member had an operation so was not able to get to store to return in until yesterday (23 August 2018). I was 6 days over 30 days. Product had tag on and unworn and have receipt. Asked for an exchange for a more expensive item and they wouldn't let me. I understand no refund but even not offering a credit note is unreasonable. The jacket is too small and needed to take it home to try it with my tops underneath to see that. I was not able to get to store due to very real circumstances and it would be client centric for them to offer me a credit note at least. I am only 6 days over 30 days, months and weeks I understand. Please can someone from Zara offer me to exchange item for credit note at least (V&A Waterfront store).