The $50 charge is likely because you opted in to use Data Credits.
When you opt in to use Data Credits, your account is automatically topped off with $50 (500 Data Credits) whenever your data credit balance drops below 50 credits.
You can learn how Data Credits are billed here.
Which features use Data Credits?
BounceShield (1 Credit)
Enrich AI (1 Credit)
Phone Finder (5 Credits)
How to toggle Data Credits On / Off?
Go to your Subscription Settings
Bottom Right of Page > Click "Data Credit Settings"
Toggle Settings On / Off