This is a dangerous call that has originated in Tonga. The one-ring phone call that you received is an example of the Wangiri scam, that lures unsuspecting victims into calling an International Premium Rate Number (IPRN).
The reason they only give a one-ring call and then cut is that they don’t actually want you to answer the phone. Instead they are looking for victims who will see the missed call and phone back. Around a tenth of people who receive call from Wangiri numbers call them back. Don’t be one of them because anyone who does call back will be charged extortionately for the privilege.
Protect yourself by not phoning the telephone number +6768500074. If you receive a call from this number report to your service provider on 7726.