Hi Frank,
If the 360 is deleting your recordings it's a sign that the box is faulty, especially if it's done it more than once. You can either call Virgin on 150 from a Virgin phone, mobile or landline, or 0345 454 1111 from any other phone to report a fault, or wait here for one of the forum team to pick this up which might be 2 to 3 day's.
When phoning choose the option to report a fault, then ignore all the options offered and you should then be placed into a queue to speak to someone.
You can also try a factory reset of the 360, if you haven't got any recordings you might as well go for the format disk option or select the keep recordings option and if or 'when' the box deletes everything again then phone Virgin.
Unfortunately there is no undelete or deleted folder to retrieve your recording from and the series links will need adding again when they become available on the EPG.