Tried calling an overseas number with TPG mobile network. No ringing tone at all and when connected it seemed to be a wrong number, I could only hear unclear broken speech from the other side. Tried 5 times and the same. Pretty sure the number was correct as I selected it from my recent call list. Changed to use a different phone service provider and the call was normal and successful. The receiver also confirmed that there were no prior calls from me. What went wrong with TPG international calls?