APN Setting

Name: Global Call
Address: 11/F, Li Po Chun Chambers, No. 189 Des Voeux Road Central, Hong Kong, Hong Kong
Telephone: +852 2915 1557
Price range: negotiable

iOS

Setting → Mobile Data → Mobile Data Options → Mobile Data Network → Edit APN as 'mobile' → Restart

Android

Setting → Mobile Data → Access Point Name → 1010 Data → APN → Edit APN as 'mobile' → Restart

Network Selection

Setting → Mobile Data → Network Selection → Turn Off 'Automatic' → Choose 'Global Call'