Please help

My device: Lenovo k3 note Indian k50a40.
Few days ago in my phone lenovo k3 note i found some manufacturer defect so I decided to visit lenovo gallery.
My phone was rooted and installed custom recovery( TWRP).So i tried to flash stock rom with sp flash tool but nothing happened.
Then i just tried to flash stock recovery through fastboot but this time it failed(remote:download partition "recovery" not allowed).
So i flashed stock recovery.img with 'flashify' app n it succeeded. Now i got stock lenovo recovery but ota updates are still not installing.
After solving my manufacturer defect i again tried to install custom recovery through fastboot,
so i can install custom roms coz the stock rom is not so good,but it still showing the same problem(remote:download partition "recovery" not allowed).
Now i don't have any idea about that. I think there is something with my bootloader but i didn't find any solution in my research,I don't have enough knowledge about android development,
so I'm posting this thread for help. Thank you