Can't connect icloud due to wrong country code (Apple's mistake)

I couldn't log in my icloud account. Icloud asked me to type the 6-number code (2-factor authentication). Because I had no other devices, I chose "Text me the code". However, an error appeared "Please enter the country code which matches the name of the country".

In fact, the telephone country code of Vietnam (my country) is +84. However, Apple set it as +848. Therefore, I cannot receive the passcode nor recovering my account.

Now, I have no contacts on my phone. It's very inconvenient. I have tried to call Apple support in Vietnam and Singapore many times since May 2016. However. they just asked me to wait. Until now, there has been no change.

Please help 😟

My email address is ******@******.com and my phone number is +******************.

Thanks.

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