In my experience UA takes a special care for UA international inconvenienced passengers.

Not sure about hotel, though it'd be in standard procedure. Anyway expect tomorrow, when aboard your flight, to be given a special form for you to fill - that's the form used by UA Customer Service to hand out UA vouchers - depending on fare/status you should expect a given $$$ voucher and an apologize.

Also a UA representative at EZE offering you a taxi or whatever at your arrival could be expected for all the inconvenience.