Conservative Party
Craig Williams said he was guilty of "an error of judgment, not an offence".
Predictions that the Conservatives will win more than 100 seats may be optimistic.
"I share the anger, I share the frustration," Michael Tomlinson said.
Rishi Sunak had faced calls to withdraw support for those involved in the alleged scandal.
The PM has been criticised for failing to suspend those accused of putting money on the date of the election.
But former Olympian James Cracknell said voters should still back the Tories on July 4.
And the final result could be even worse for the Conservatives.
Voters already think the PM is weak and the controversy has only reinforced that opinion.
The Conservatives' head of data is the latest senior official to be dragged into the scandal.
The Conservatives have fallen even further behind Labour with less than two weeks until polling day.