if the registration book is not stamped with FILE return, the original file is still in Excise office custody at Civic Centre Karachi.
@rare
number plate missing, & tax paid outside SINDH is invalid means the the excise tax is at default subject to penalty upto 30% of default amount. The 2 points are sadly Negative .
You may ask some friend or relative in Karachi to visit Civic Centre excise office during weekdays between 11 am to 2 pm and verify record of vehicle with excise office print out. You only need to share the vehicle registration number with your contact, agent will charge Rs. 300 for such data print out.
you can also get an update of car status from - Welcome to official Web Portal of Excise Department, Government of Sindh - input the vehicle registration number