The charging schemes of roaming services differ among overseas network operators and are subject to the volatility of exchange rates. You should check the charging details before making any roaming calls. Roaming tariff tables, setting out the highest and lowest rates, are usually for reference only.
Currently, all mobile service providers offer roaming services to their customers. Most of the providers require deposits from their customers. Usage charges will be incurred when a customer uses roaming service. As the charge is relatively expensive, you should terminate your service immediately if your mobile phone is lost or stolen. Otherwise, you may suffer heavy financial loss.
Furthermore, some service providers may set credit limits for roaming service to protect their companies' and users' interests. Service to a customer may be suspended temporarily if there is a sudden surge of roaming service usage or the total roaming charges exceed the pre-set credit limit. The customer will have to settle the outstanding payment before he/she is allowed to continue using the service.
Roaming service providers constantly review the credit limits set for their customers. If a customer's usage steadily increases, the service provider may automatically raise the customer's credit limit. However, to avoid any inconvenience, if you need to raise your credit limit temporarily, please contact your service provider in advance. Your service provider may require a deposit or credit proof for reference to process your request.
In Hong Kong, call forwarding service is commonly used by mobile phone users. With the service, incoming calls are automatically diverted to a designated local telephone number or voice mailbox when the called party is not available or when the phone is unanswered or busy. If you activate the call forwarding service before leaving Hong Kong , all incoming calls will automatically be diverted back to the pre-set Hong Kong local telephone number or voice mail box when you are unreachable or when your phone is unanswered or busy. As such, two roaming charges will be incurred, including the roaming charge for the call from Hong Kong and that for calling back to Hong Kong, even though you have not answered the calls.
To avoid paying unnecessary roaming charges, you are advised to deactivate all call forwarding functions before leaving Hong Kong. You may reactivate the functions when you are back to Hong Kong. You are also advised to check out the details of the roaming charges direct with the operators.