United Bank Of India [UBI] — Regarding Debit card

My name is SREEJAYAN T M I am having S B Account at UBI KOZHIKODE. My account No. is [protected]. My UBI Visa Card No. is [protected]. In India I was using the card for shopping and withdrawing money from ATM.. Last week I have visited Malayasia and Singapore. First two days I was in Malayasia and there was no problem with the card. After I reached Singapore, I used the Card for withdrawing money, & shopping. I used the card at different places and all the places the swiping machine was not accepting the card. Please inform me the reason for not accepting the card at abroad. My E mail ID is [protected]@yahoo.com Mobile No [protected]