Diamond press coffin box

I am once again very disappointed with the diamond press stock availability. I watched a video on YouTube showing the Coffin Box die cut and stamp set. I went to the diamond press website and it was already sold out. It’s not even showing on HSN craft site. Why does Diamond Press carry such a low volume of supply and teasing us with videos? I don’t think it’s very good practice as it’s very frustrating and disappointing. Any suggestions as to how I can be more successful in the purchasing process? Thank you for any advice and feedback