HP Shop ignoring my purchase and not delivering

Order # H***0100 I ordered printer cartridges and paid in full on 8 May expecting them to be delivered soon. Only after I had paid, did I receive an email that the order was on back order as they did not have stock. On 11 May I received an email that the stocks were expected that week but that was the last I heard from them. Retails stores are selling these cartridges now, some much more expensive than HP Store, but some cheaper. However, I cannot buy from them without knowing if HP Shop is going to send me my order. They do not answer their phone and they do not respond to emails.