I'm not receiving E-mails anymore?

p.s Hi I have 700 unread emails currently (said this as i though it might be to do with the problem, i doubt it though)

Anyway, since 19/03/2015 i have not received a single email. Prior to this date, i was consistently getting around 10 emails a day so it is definitely a problem.

I cannot even think what might be happening as the situation is so bizarre.

Does anyone know what is going on?

Thanks,

Adam