you have to change your sim with retaining the same number. just go to your nearest sim card gallery of which your sim is and ask them to give you new sim card with same number your problem will be solved
You can call the customer care from the same company other SIM card(Lets suppose that said Phone have Airtel so use any other airtel number to call customer care) then ask tell them the phone number and the details they ask you and they will tell u the PUK code.
When u get that make sure to disable Sim Pin in settings of ur phone. (Settings > Security> Sim card pin)