I need a battery for Chuwi Ubook Pro

I am from Mexico and Chuwi can not send me a replacement of my battery, where else can I buy it or how I adapt one to the equipment, I am sorry to have bought the equipment, Chuwi support does not solve anything, I already contact them by mail, I deposited the cost of the battery and I continue with this useless paper step

Have you already tried it on Aliexpress?
You can usually find all batteries there.
Neue Batterie Für Chuwi Ubook / Chuwi Aerobook CWI509 HW 31130148 H 31130148P Tablet PC 7,6 V Ersatz Akkumulator 7 draht stecker|Digital Batteries| - AliExpress % 22% 7D

Alternatively, you can also ask electronics dealers in Mexico.
The battery types are usually used in several types of tablets from different manufacturers. Teclast and Wortman, for example, use the same batteries.
It is only important that the voltage, the plug and the size (a little smaller is also possible) are correct.