Dixons online has given me very poor service. How can I make this known to other potential customers?

I placed an order for a hob on 22nd May and received an email stating my order was being processed. On 27th May I telephoned to enquire about progress and was told the item would be in stock on 3rd June. On 4th June I telephoned and was told the item would be in stock on 17th June. I cancelled the order and was able to get next day delivery from a competitor.