Wrong plot size as per allotment letter / map of bahria town ph-8, block l

I have purchased 7m plot in bt ph-8, block l but as per map the plot is in 10m category. So while i apply for procession, came to know that i cant get possession till correction of plot size.

I have given the request bt office to correct the size but still no update.

Can anybody suggest what could be the solution / procedure to resolve this issue.