Advice needed on rescheduled tickets

srahmb

I purchased 2 tickets for a concert in London and changed my mind so re-sold them via stubhub. The concert was originally in March and got postponed due to Corona to September. I have just been advised that it has been rescheduled again to a day later - it’s in 1 weeks time. The seat numbers are different and the face value cheaper by £8. Stubhub haven’t acknowledged the new date (as they did for the first reschedule) so I can’t see how the buyer will know either. If they turn up on the original date the sale will be invalid and I won’t get paid. At worst I would want a refund from the venue. What am I entitled to from who in all of this and obviously I have 4 working days to sort out ! Thanks !