delivery delays without looking into impact

Online order placed 28th November and im promised there is stock. I follow up and am told there is no stock and im on back order and that they are still within 3 to 7 working days SLA. on delivery date i call and im told its with dispatch. I call again in the afternoon and im told courier will call me sometimes during the week and that they cant do anything if there is no stock. 1. only reason i went with the deal was due to being told there is stock 2. no contact made to me on the number i provided as contact 3. despite knowing that its behind schedule - courier wasnt contacted and i had to ask that they contact the courier to prioritize you internal process failures have nothing to do with me - if you say there is stock but the isnt - it means you **** to get me to take your deal