The phrase "ask whoever" is correct and usable in written English.
It can be used when you want to suggest that someone can inquire with any person they choose for information or assistance.
Example: "If you're unsure about the schedule, just ask whoever is in charge."
Alternatives: "ask anyone" or "inquire with whoever".
Otherwise, you'll have to ask whoever posted it to remove it.
"In four years, people are going to ask whoever is president: Did you solve the Social Security problem?
Ask whoever runs the board for details about how many candidates they have on file, and how much traffic they get.
But, first, be sure to ask whoever owns the beach – it could be the local council, the National Trust or an individual.
So about 7 40 or 7 45, we have a big sign that says, "Last in line for the day," so we'll ask whoever is last in line at that moment to hold that sign.
One of my experienced colleagues, Andrea, stays late for hours after every shift, comes in on her days off, and phones up at night to ask whoever is on duty to check on her patients.
I asked whoever found the letter to contact my wife.
A second plea on Friday said: "Once again I am asking whoever is faxing the contents of this site to British members of parliament to please stop.
The registry will replace a creaky system that relies on, among other things, random-digit phone surveys, with researchers asking whoever answers whether anyone there fished and what was caught.
When the young French soldier Louis Althusser was taken prisoner of war by the Nazis in 1940, he tossed scraps of paper out of the train that was carrying him away, asking whoever found them to send them to his uncle in Paris.
It then emerged that in June 1992, a Visegrad police inspector, Milan Josipovic, had received a macabre complaint from the manager of Bajina Basta hydroelectric plant across the Serbian border, asking whoever was responsible to please slow the flow of corpses down the Drina.
