Does the tenant have a receipt for the deposit?I asked the LL for advise and TBH he wasn't very helpful. I think as it is my problem he handed it back to me to deal with. However, I can understand why as essentially it really has nothing to do with him as I took on this guy, not him and I have his deposit.
I'd be very surprised if Threshold tell me today that he can get away with 1 days notice even if it was just a verbal agreement.
If you've no lease agreement and he's no receipt I don't see how anythings inforceable. 1 days notice is not right - there may be no legal agreement but it's not right. Hold the deposit and the explain the situation clearly and concisely to Threshold, or whoever, contacts you. Don't be bullied by legal mumbo jumbo into giving it back. Make him prove his case if needs be.
The PRTB has no jurisdiction on sublets, in fact I'd be surprised if anyone does. The tenants rights are virtually zero in cases like this. Threshold has no jurisdiction over anything.