Really shocking customer service

I recently did my first order via ZANDO app for a dress that I need for an event that is happening on Thursday 13/12. I have been informed delivery will be Friday 14/12 which doesn't help me , I sent an email to support with no response to date and I called after holding for almost 15 mins spoke to a lady who was rude and arrogant telling me how I should have read it stated 5-7 days delivery not considering my dilemma of not having anything to wear for a very important event on Thursday or even apologizing but just stating i should have read what the site said about delivery time frames. Considering I placed my order on the 4th even 7 days would be Thursday. This is really appalling service and I am shocked seeing as though its my first interaction with the company.