To move to a new phone, make a Portable Backup (a .vkbak file) in Settings, send it to the new phone any way you like, and restore it there. Your shop name, bills, Khata, items and photos all come back.
A lost or broken phone can only be recovered from a Portable Backup you saved somewhere else, such as your own Google Drive, so make one now and then. The nightly Device Backup (2 AM, last 7 kept) lives on the phone itself and only restores on that same phone, on purpose. Portable Backups are not encrypted, so share them only through channels you trust. With no backup elsewhere, we can’t recover the data.