Recovery mode options not as expected

[Got2know]

I bought an unlocked, used Cubot S222, which turns out to be rooted - with Superuser (crowned lion head icon, copyright 2014 Xinyi Inc) . The total phone storage is 858 MB (should be around 12 GB as the ROM is 16GB). I went into recovery mode, but there is no option to delete cache/remove partitions. Only to test board/item/full auto/clear eMMC/board info/reboot/power off/Chinese factory.

I cleared eMMC, but phone still the same. Another thing - clearing eMMc or doing a factory reset through settings options completely drains the battery despite only lasting a few seconds.

I look forward to some useful information and advice (nothing like 'return or ditch the phone' please).

Thanks for reading.

I just got to know.