Realme c2 RMX 1941EX display graphic problem after unlock ufi

I don't have ufi box so I gave to unlock other person.

Realme c2 display graphic problem after unlock ufi.
When I on my phone then phone is doing vibrate and start with blank display.
When phone is completely on then display being black and white.

Please give me any solution.
How can I recover my phone in good condition?????
Is it software problem or hardware problem?????
customer demanding his phone in good condition.

Online flashing can solve my problem or not???
I am in the trouble .Please help me expert.Sorry for my bad english

Thanks in advance.