let's say me change $400 of epicentre vouchers from UOB...
another $500 from DBS and another $500 from standard
chartered.... all change for epicentre vouchers...
Can I combine all of them and change for 1 item in epicentre? or
can i buy 3 items and charge the outstanding sums to individual
credit cards?
Nope. You have to buy 3 items.
$500 for 1 item, $500 for 2nd item, $500 for 3rd item.
So if you change $1500 and your item costs $1600, you have to pay
$1100 balance with a $500 voucher. The other 2 $500 voucher
have to use it on your subsequent visits.