Bootloop and fast discharging battery

Hi my tablet CHUWI HI9plus have a problem of fast discharging battery pass from 90% at 80% in 5 minutes and later closes now i have do a wipe data factory from the recovery menu but now in configuration of the new tablet the battery is a 50% and has constant bootloop problems.could i fix it by installing the latest firmware available? I tried to use the available version (my tablet has the red button and is 4 gb of ram and 128 gb of rom) but Flash Tool give back a error “The Loader Scatter File is Invalid” i used this version of firmware “CHUWI X20P_6797_8.0_4+64 Dual mipi_2K_3H2+3H2_20180820+CH1005-0420” and “SP FLASH TOOL” finally i have installed a MTK driver for my 64 bit system operative.
What should I do?

Thanks

Hello
Please give me the exact model and serial number, and I will find you the exact system files and brush tools to send to you.
thank you

Hi9 Plus Type: CWI515

Hello
Cwi515 is not a serial number. Its serial number shall be on the SM card slot.

Hi9plusE128G1940573 it s ok?

Reading this on a new device, the only answer can be warranty. return for new item.