Sagging mattress-Cloud Nine

We bought a Cloud Nine mattress in Dec 2025. It started to stag, I submitted my first complain 8 June 2026. Second complain & followup 29 June to repairs. 30 June with ticket nr ***, 10 Aug another followup with new ref nr SM-CLOU-***. No feedback at all, and in the meantime we are suffering on a (new) hollow mattress. This is totally unacceptable! The branch we bought the mattress is following up with no feedback. They keep on telling us there is no stock. I CANNOT ACCEPT THIS AT ALL.