Dress not delivered

I bought a dress online on the 31st October. Their SLA is 5 working days, this means I should have received my dress on the 6th of Nov. On the 9th of November I followed up and I was told they will send tracking details, I kept on following up to a point where I called and was told that they can't search for my order because they're offline and they will give me a call. I haven't received a call since.