The obvious things to check first are
a) the power supply - has your fuse blown?
b) is there power to your control unit?
b) are there ant indicators showing on your control switch - check these in the instruction handbook for advice
Thereafter the best thing to do is to call the MV Airo direct support line on 02380 522 345, they are very knowledgeable and helpful. The heaters all come with a 2 year warranty so they will get you sorted. If you dont find a resolution quickly through the support line then please do give us a shout and we'll get on the case for you.