"For one week only we will give full BTC refunds."
So when they were already delayed by months one week wasn't enough for you to make up your mind? You thought you could still make a profit from B3 and hence didn't cancel, don't blame your choice to gamble on someone else, there was a way out and you decided not to take it.
Also it was more like 2-3 weeks from the end of the "refund request" window close that the first B3 units started showing up. I was very late in B3 and my miner showed up about 3.5 weeks after the final refund request date.