Srilankan Airlines — flight refund (flight ul307)

I purchased two tickets from sri lankan on july 12. On the same day, i called customer service to cancel the tickets, and i was informed on this call that i should do the online cancellation, at a cancellation fee o[censored]s20 per ticket. I provided sri lankan the protocol number for the call where i was informed the wrong amount, which they did not check. I applied for the refund, as recommended, and received an email saying the refundable amount would be informed to me in two business days. I never received the email informing me of the refundable amount. I have received the refund in my credit card, and was surprised to see a cancellation fee in excess o[censored]s240, which was both higher than the amount i was informed on the phone and unexpected, as i was never informed the amount i was going to be refunded.