Missing MX Records

My email is no longer working which is connected to my domain name server but the MX records need changing. I have no idea what's happened. All payments with hosting and domain provider are up to date. My previous web developer enrolled me onto Cloud Flare without my knowledge and now it's gone down. I have tried to register an account but to be honest unsure what to do. I need help and for this to be resolved ASAP please.