Whatsapp Business backup is not working . also iphone heats to much & battery drain to fast

I have 2 WhatsApp , first WhatsApp & second one is business. the second one 's chats are very important for me so i want to backup these chats to iCloud & iTunes. but im trying to do these from 8-10 days but its not working. it takes hours but after that are fail. i do in WhatsApp business chats backup section it also not working. thats worst experience from apple that how much people will facing these problem. people will trying to switch from android to iPhone & pay much of there money. after purchasing they will facing these problem. when i was switching to android to iphone i also face these problem my first WhatsApp chats easily transferred but business WhatsApp was not transferred . i also purchase iCloud storage but same. apple always wants to take money for small things not to resolve there product's weak things. i go imagine store for these they also not helping regarding these concerns. after purchasing iPhone i put sim after 2 months regarding these concern. also my battery drain very fast . after 80 percent charge it take 1 hour + to charge more. & after every 10 minutes phone heats to much . its 5 month i purchase this in feb end