Banned WhatsApp and unable to retrieve WhatsApp backup

Hi guys, I was using WhatsApp business all this while and all of a sudden yesterday I got a notification that I did not adhere to Meta’s policy and I got banned. After the ban I couldn’t enter WhatsApp at all but there was an option to appeal which I did but wasn’t approved. I did not do anything wrong and I’ve only used WhatsApp solely for work and personal. The only option for me was to change my number to use WhatsApp. After changing my number, I couldn’t restore my WhatsApp backup at all. I’ve tried all the options I could think of except using a third party software which I’m afraid to use.

I kindly seek anyone’s assistance here on how to solve this issue. I have messages of my late mum and many other important work messages that I really need back.