It’s the classic Nigerian email scam with a PCH twist.
You get an email saying some Nigerian nobility left you a huge sum of money but to claim it you need to wire “just a fraction” of it to some third party (usually with some government sounding name like “Nigerian Minister of Finance” or some such).
Any call or other correspondence that asks you to “wire” money to collect a greater sum is a scam, period.
PCH (as all reputable lotteries) state clearly (if not in the fine print) “taxes are the sole responsibility of the winner” meaning YOU pay the taxes YOURSELF to the IRS. They don’t withhold a portion or take the taxes you owe and pay the IRS for you. You pay them (with the help of a competent tax attorney and financial advisor preferably).
It’s a scam. Report the number to any authority you wish (your phone company the Feds the local police) and accept your real financial situation whatever it is.
Your data on lottery winning witholding may be out of date. Powerball and Mega Millions prize over $500 or $600, can’t recall exact amount, have both Fed, State, and sometimes local with holding on prize payouts. Fed is just under 40%. So I rather doubt PCH winners, being such juicy targets are exempt. Win a car, boat, whatever, you owe taxes and the gov gets theirs first. You may or may not recover portions of that depending on your tax situation.
Based on my experience of winning a 5 figure prize some 20 years ago. Don’t imagine the IRS has relaxed their talons on this matter.