Possible find my iPhone phishing scam

A scam unless you actually lost yours.

These are scams and should be ignored

1. Identify and report phishing emails and other suspicious messages
2. Annual Reminder- Watch out for email Phishing Scams
3. Identifying fraudulent "phishing" email
4. Beware of Browser Pop-Up Tech Support, Phishing Scams
5. Phishing & Other Suspicious Emails
6. Avoid phishing emails, fake 'virus' alerts, phony support calls, & other scams
7. Phony "tech support" - "ransomware" popups and ... | Communities

Report phishing email to abuse@apple.com.

Reporting phishing and other attacks to Apple

iDevice Safari Phishing Adware Popups

1. Your device does not have a virus. You can fix this as follows:
2. Kill Safari by double-tapping on the Home button. Locate Safari in the task bar, then slide the Safari mini-page upwards so it vanishes.
3. Tap Settings > Safari > Clear History and Website Data. Next, locate Security section and slide the “Block Pop-Ups” switch to the On position.
4. Press the Home button to return to your Home screen.
5. If this doesn’t help, then reset your device. It won't delete your data. Press and hold down the On/Off button and the Home button until the display turns off and returns with the Apple logo showing.

Alternatively, follow these instructions to reset your device: Restart your iPhone, iPad, or iPod touch - Apple Support.

That is a scam even if (and especially if) you actually lost yours. It is a common way for whoever currently possesses a stolen device to attempt to get your password so that they can remove activation lock.

It is definitely a scam.