Waitrose Customer Assistant interview questions

I interviewed in November for a position due to start before Christmas. Interview was easy, just an informal chat with the manager for 10-15 minutes. I was told they would get back to within 2 weeks but that it might be more because of the Christmas backlog, which wasn’t a problem! I then had to chase towards the end of December to ask about start dates as I hadn’t heard anything. I was told at the beginning of January that my start date would be on the 6th - which was perfect. The 6th came and went with no correspondence from Waitrose, I had to chase them up a few days later to ask what was happening. I didn’t receive any replies to my email for just over a week, in which time I was told that they were still waiting back on contracts and no longer have a specific start date for me. I’d turned down other job offers in January as I had believed I was starting Waitrose on the 6th. I then received a call last week from a manager asking if I was “still interested” in the job, despite already previously been given a start date and waiting 2 months??? I’ve since found myself another job that I have started today and told them to keep the one they seemed to never be able to get sorted for me- I lost out on job roles and money because of Waitrose being so unorganised, and the communication was non existent!