Net4.in — Domain renewal / transfer

We have registered our domains on Net4.in since more than 15 years. Now, they have taken payment for renewal of our domain for 10 years. But didn't provide invoice copy or receipt. Not reachable by phone / E-mail.
Even our domains are locked for transfer, so we are unable to move out our domains.
It is requested to you to at least arrange to unlock all the domains registered with Net4India of all the customers, so users don't get trapped like us. This is needed to be done as soon as possible.