Contact addresses gone missing

[#1]

Not sure if Plusnet can help but have nothing to lose by asking.
My computer is kapput, harddrive gone, nothing can be retrieved says the fella looking at it for me. 
My computer is my lifeline to the outside world. It is especially adapted for me ( I am blind ). I have all the software to enable someone to set a new pc up for me. My problem lies with my emails and address book in Plusnet. Everything prior to 7pm on 24th Feb has gone missing. My read emails , my address book contact details. Sent folder empty. It is as if nothing existed before that time.
I have no idea of techy stuff but could staff here let me know if there is any way of locating any of my older stuff or will they be lost in cyberspace.
I have function keys and menus, do not use a pc the way most here will.
I would be extremely grateful for any advice.
Many thanks

[#2]

Hi Sheepdogs,
I've had a chap with one of my techy guys here and whilst he doesn't think we'll be able to recover anything for you, he's going to give you a ring in the next half an hour to see if there is anything that he can do to help.

[#3]

Much appreciate anything you can do. Nothing ventured nothing gained.