I'm asked for my registered phone # and PIN

Question

Why am I asked to enter my registered phone # and PIN?
When you call your Skype To Go numbers, you are identified by your registered phone’s caller ID and won’t need to enter your registered phone number and PIN for authentication purposes.
There are several reasons why you could be asked for your registered phone number and PIN:
You are calling your Skype To Go number from a phone which is not registered in your account yet. You can register more phones anytime in your Skype To Go account overview.
You are calling from your registered phone, but you may have made a mistake when entering your phone number in your Skype To Go account. Please check that you entered the correct phone number.
Your phone does not submit its caller ID. In your phone’s settings, ensure your caller ID is enabled. Your phone may also submit a caller ID different from your actual phone number (e.g. when using an office phone).
You may be calling an old Skype To Go number which you previously deleted. Please sigh in to your Skype To Go account to ensure you are calling the right number.
If you are still experiencing problems, then please submit a ticket with customer service, including your Skype To Go number and the time & date you tried calling.
Why does my verification fail after entering my registered phone # and PIN?
If you call your Skype To Go numbers from a phone not registered in your Skype To Go account, then we will ask you to enter one of your registered phone numbers along with your PIN for authentication purposes. Should you experience problems during this verification process then please check the following:
Please ensure you are entering the phone number of one of your registered phones, not the number of the unregistered phone you are actually calling from. You can register more phones in your Skype To Go account.
When prompted, enter your registered phone number in this format:
Country code + phone number + the “#” key
Example 1: You live in the US and your registered phone number is 333-444-5555, then enter:
0013334445555#
Example 2: You live in the UK and your registered phone number is 07777-888-999, then you enter:
00447777888999#
Please check your registered phone in your Skype To Go account. You may have made a mistake when entering your phone number.
If you are unsure whether you entered the correct PIN then create a new one
You may be calling an old Skype To Go number which you previously deleted. Please sigh in to your Skype To Go account to ensure you are calling the right number.
If your selected PIN starts with a "0" then verification may fail. This is due to technical issues which we are in the process of fixing. Please change your PIN to another one which doesn't start with a "0".
If you are still experiencing problems, then please submit a ticket with customer service, including your Skype To Go number and the time & date you tried calling.
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Answer 1

If you have forgotten then these links are the only way to resolve
http://www.apple.com/support/appleid/
As long as you have owned the iPhone from new and your Apple id is the one used to activate when new
OR have you recently purchased the iPhone secondhand ?