As developer you don't have "cash on Steam account". Valve just do automatic payouts to a bank with a delay around ~1 month.
As for refunds AFAIK if you have bunch of refunds later they will just be substracted from future sales. But games I worked on didnt have refund spikes so no clue how Valve handle situations with mass refunds.
As for refunds AFAIK if you have bunch of refunds later they will just be substracted from future sales. But games I worked on didnt have refund spikes so no clue how Valve handle situations with mass refunds.