mistakenly

I was mistakenly assumed to be a Welshman because of my surname.

I mistakenly deleted all my important files.

She mistakenly thought the meeting was at 2 PM.

He mistakenly took the wrong train.

They mistakenly believed the rumor.

The cashier mistakenly gave me the wrong change.

I mistakenly left my phone at home.

She mistakenly thought today was Friday.

He mistakenly entered the wrong password.

They mistakenly assumed the store was open.

I mistakenly sent the email to the wrong person.