Some users who made electronic payments last Wednesday, including via DBS' PayLah app, had their money unwittingly deducted twice.
Payment service provider Nets noted in a Facebook post on Friday night that some people may have had "temporary difficulties" while making Nets QR code payments due to connectivity issues from 11.59am to 12.33pm that day.
Nets said that its QR code system had encountered an "unexpected scenario" that prevented some payment requests from being completed. "This resulted in an unusual number of failed transactions, which was picked up by our monitoring system and the matter was rectified immediately."
It said duplicate transactions may have occurred if users had made a few attempts to pay during this period, and added that the system's security was not compromised and enhancements have been made to ensure similar incidents do not recur.
DBS' PayLah, OCBC Bank's Pay Anyone, United Overseas Bank's (UOB) Mighty and Nets' own NetsPay all use the QR code system supplied by Nets.
OCBC's vice-president of group brand and communications Dominic Ying said there were no incidents of double payments for OCBC Pay Anyone users that day. A UOB spokesman also said customers have not reported such issues when making payments on the UOB Mighty app.
A few PayLah users have posted on the DBS Facebook page complaining about PayLah issues.
Nets said in its Friday Facebook post that it is working with DBS to refund PayLah users for duplicate payments. These should appear in three working days.
Nets advised users to check their e-wallet balance and transaction history, and to e-mail info @nets.com.sg if there were discrepancies. It added: "We apologise to users who were affected by this incident."