No delivery, no (adequate) feedback

I placed and paid for my order on 25th November, delivery was supposed to take place on 4th December. A package was delivered on this day but only 3x of the 4x items ordered were included in the package. I sent an email query on evening of 4th December after I’d opened the package asking where the 4th item and expensive pair of metallic distressed leather superga shoes. 24 hours later after not having received a response I sent a follow up query. The response I received after the second query said that the matter was being looked into... since this time I’ve had to send several additional follow ups as no information has been forthcoming and when my follow up queries are responded to all I’m told is that the matter is being looked into. I have asked that my new delivery date is confirmed or that I’m refunded but neither of these have been forthcoming. Today I called the call centre and spoke with a consultant and her supervisor to try and reach resolution and explain that it is hardly fair or good customer service to leave me waiting while they decide where the weakness in their system that allowed my purchase to go missing is. I was promised that I would receive an email indicating that a new pair of shoes had been dispatched and once again this has not been forthcoming. While service I’ve experienced in the past has generally been good, it is now blatantly obvious that Superbalist.com do not know how to deal with things when there is a glitch and an item is not delivered. I am out of pocket and out of time as the item was purchased as a gift and I will be away soon. How can it take more than a week to locate a missing item? And then still not know where it is or give the customer feedback. Please may my delivery date be confirmed or my purchase refunded. Thank you.