TIME
You can block foreign phone calls by using the following methods:
1、Adding the foreign phone numbers to your phone’s blacklist or contact list to automatically block incoming calls from those numbers.
2、Using your phone’s settings to block all unknown or unrecognized numbers.
3、Using a third-party app that specializes in blocking unwanted calls or spam calls.
4、Contacting your phone service provider and asking them to block foreign phone numbers or international calls.
In English, you can say: "How can I prevent incoming foreign phone calls? I’d like to block them."