To start with can you advise what is shown on the display, are any numbers shown?
Secondly what indicator lights are on and are any flashing?
Can you please advise which of the two function buttons are not responding.
Ok, so there is no sign of life to the dishwasher at all.
I would start by checking the fuse in the plug for the dish washer, and make sure the socket to the dishwasher hasnt tripped.
If both are ok, the fault is looking likely to be a faulty control board, which will require an engineer call out to replace it, the part is around £80 from here.
If after checking the socket and the plug fuse you would like me to recommend an engineer to come to site, please provide me with your postcode.
So if its not registering the buttons this is likely a fault in the PCB where the signal from pushing the buttons isnt being registered on the unit, to rule out a faulty button it may be worth turning the machine off and spraying some WD40 in and around the button as you press it in, give it 10 minutes then turn it back on and see if it starts working. If it doesnt then it will need a new PCB which is part of the control board.