Many people here don't hang the UpDown's signature anymore, but why you still demand the payment?I don't think you will be paid. Even the people sticking with him haven't been paid yet.
I guess he will pay you. UpDown is one of the BitcoinFoundation Gold Member(https://bitcoinfoundation.org/members/) ,that means they donated 100 thousands dollars to the foundation,so I think they won't run away for so little money. Maybe he have came across some issue with his healthy,he mentioned this case. So , just clam down and give him more times.