If you have updated a V6 box to 360 and it's deleting your recordings it's a sign that the box is faulty, especially if it's done it more than once and you have tried a factory reset. 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.