Hi this is the same with our family too. Paid a huge sum and OC delays since 2 years after they promised OC clearance.
The project has not been constructed but all upfront payments they requested are made. For cancellation, no option is given.
We also cannot understand how to get out of this situation, or at least get an honest answer on if the OC is expected to come or not.
The team has said this OC is required to construct the project too.