Bad Customer Service

Phoned Decofurn on 27 Feb to complain about a mattress that has sunk in the middle after 2 months. Was told to send an email which was done on the 29 Feb 2024. Received case number ***8 and after numerous emails to follow up, after 3 months still no response. Service is pathetic, after numerous calls as well, keep being told the Supplier has been emailed. Is there no Escalation process with the Supplier?