It sounds like the scope configuration has been wiped from its memory. The software is seeing your scope as a mark 1 ADC-200, which had a switch on the unit and so didn't require the option in software.
We can reprogram the unit for you free of charge and this should fix the problem.
Could you email your contact details (name, address, telephone, email) to email@example.com
and we will arrange for you to return the unit?