Terrible Product and Service

I bought 2 phones off Amazon, one last year (2024)November and the other this year (2025)February. Both switch off randomly and restart or glitch and this is all months before their full one year warranty. I emailed and placed a complaint and sent proof of payment for both and was told they would get back to me within 24 hours, it’s been 72 hours and I’m yet to receive a call or follow up email. When purchasing the phones everything was smooth sailing but now to follow up on them is taking them days? Absolutely unacceptable. I want a replacement for both or a refund and I know for future reference to NEVER buy off Amazon again.