cartridges ordered on December 6 not delivered

O rdered hp cartridges worth R834 on December 6 , paid by eft on December 8 and followed up with numerous proofs of payment . On June 30, I adjusted a slight underpayment of R79.02 by eft ,followed by proof of payment. I have made 11 phonecalls in total and written four letters ,to NONE of which have I received a single reply. I have not once been able to speak to the same person twice and have been consistently refused access to a more senior person. Will start suing for recovery of my payment on Monday