Can I still register if I do not have a Singapore registered mobile phone number? March 25, 2019 04:00 Updated Yes, you can register using a foreign number, if SMS service is available. A one-time password (OTP) will be sent via SMS. Related articles Will I receive notifications from Maxi-Cash app? What else can I do besides paying interest on Maxi-Cash app? Is Maxi-Cash app the same as iPayment web?