No response to deliver correct items

Placed an order 29th July. Order delivered 3rd August. Sent an email on the 5th to tell i have the incorrect item. They responded on the 7th to say they will escalate it to the relevant department. Sent another email on the 11th because i have not been contacted. They responded the 12th to say the will follow up when the correct item will be delivered. Its the 19th August and no one has contacted me.