Its most likely because of the fact you changed the phone number.
If you were using the original phone number you used when creating the account this most likely would not have happened - or would have been a simple matter to resolve.
As it is youll most likely have to call in - which is never a good thing (although its not the end of the world).
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AGED SUPER HIGH LIMIT ACCOUNTS: 10,000/$1,000,000 and 25,000/$500,000
How comes you can withdraw after 45 days? do they not hold it for 180?
I assume it's like that: I have stealth account A and stealth account B, paypal linked them together because a buyer called them, I mistakenly messaged her through my stealth account B email for an item she bought via stealth account A eBay. Thus she provided both account email address to paypal, since stealth account A paypal is limited half year ago, the stealth account B got limited as well, and after 180 days the stealth account A is able to withdraw, that is probably the reason why the linked stealth account B is able to withdraw as well.