Bait and Switch?

This company approached me with some attractive quotes for a solar installation. They then followed up a lot, emphasizing the need for speed lest their stock run out. I accepted a quote and then, as required, paid the invoice in full on 20 August 2025. On 5 September they were waiting for "one last component". Since then, they send me the odd update about production delays and where I am in the queue I was 9th, now I am 10th! I have twice tried to cancel and get my money back, but that gets ignored.