Horrible service!

I ordered Crocs from the Croctober sale on the 22nd of October. I accidentally ordered the wrong size and sent an email on the 23rd and asked that they change my order to the correct size. They told me it’s not possible as it has already been allocated and processed and that I’m welcome to send it back once I have received them. I was okay with that thinking that in the next couple of days my order will be shipped so in a week or two I would have the correct size. But boy was I wrong! I emailed numerous times asking for an update on my order. The courier collected it only YESTERDAY from Crocs! On the 23rd of November. How is it possible that in a months time they couldn’t change it to the size I requested? It took them an entire month to ship my order. I received a sms from the courier that they will deliver on the 25th. Horrible horrible service from Crocs. Now do I wear the wrong soze or do I send it back and wait another month or two for the correct size?