@NingHuang1987 - if you didn't get from the other posts, there are no Public Mobile services available in China, sorry.
Open up the The Fine Print in this area to see the rules of addons: https://myaccount.publicmobile.ca/en/account/manage/shop/addons
See # 8 about the International Calling addon you purchased.
Interestingly #3 just states "Roaming applies outside of Canada." I suppose you could argue the wording here. But the addon titles are listed as "US..."
the only add-on that will work for roaming is the 15 Day US Roaming add-on. That add-on is for use whilst roaming in US only. If that didn't work whilst in US, you might get a credit to your account if you ask for it. In the future, come here to the Community Forum for suggestions on how to get the roaming add-on to work. There's a few hints we can provide to help.
The International calling add-on that you purchased, is for use to call a few specific countries listed in the menu... BUT...the call must originate in Canada. As that add-on works as advertised, you likely won't get any refund or credit. The good thing is that the add-on will stay on your account, until you do use it up...even if it takes several months or longer.
Going forward, I'd suggest you at least do some reading about what you're buying BEFORE you buy it. That's sorta like buying a Hyundai, then later, wanting a refund because you can't pick up chicks in it ! 😎
Roaming add ons only work in the US with pm's roaming partner T-Mobile. The 15 day US Roaming add ons start counting down to their expiry immediately after purchase. If you purchased too soon before your trip you may ask customer support if they are willing to credit your account for your misunderstanding.
International calling add ons only work when calling from within Canada to the international destinations listed. Calling minute add ons do not expire rather roll over every 30 days until completely consumed.
@NingHuang1987 LD Calling is for used to call FROM Canada to other counties
Roaming is for use in US, need to connect to T-MOBILE first.
If you would like to check if support can reverse the transaction, message support here: