Chat backup


I went to whatsapp chat settings and it told me "the file is too big to backup over cellular data please connect to wifi if you want to back up"
Unfortunately my wifi on my iphone is broken so the only option I have is using cellular data. My auto-back up was set for monthly, but it never backed up since the file was always too big to do over cellular data. I clicked back up now, because i really wanted it to be backed up since im getting a new phone soon. But now all my money is going, all my MBs finished but the process is not done. The things is, the wheel of the whatsapp chat back up is still turning, even though there is no MB or money left on the phone. So I am guessing, that when i put money again, it will take that money and use it for the chat back up. I tried, but there is no way to turn it off, i went to icloud settings and turned of the icloud drive, i swithced off cellular data for whatsapp, and i even switched off my phone. But nothing works. And I still want to whatsapp, and not have all my money go to a chat back-up. Please, is there some other way to switch it off. I would really appreciate your help!