UK Landlord Forum / Life

can someone help me please. My tenant told me she was leaving via e mail it was a formal months notice on the 20th July she then changed it to 1st August she then changed it to the 9th August. I then received another e mail to say she had lost the phone number of her new landlady and was'nt sure when she was leaving it may be the 9th August still. I am reliant on her rent to pay my rent and I live 400 miles away
I began to apply for jobs back home with intention to live back in my house as she was leaving . I'm now having to cancel my interviews due to the tenant messing me around! as I don't know when she is formally leaving.
I have e mailed her last week telling her that I need a definate date otherwise my young son and I could be homeless and jobless due to her. She has stopped responding to me!
Should I send her a notice to quit?
She says her landline is broken and lost her mobile the only way of contact is via e mail.
I am at my wits end with this woman, I asked an estate agent to go in to value the house to rel-let and he said it was very dirty including carpets etc and I must get her out.