https://wccftech.com/google-accidentally-charged-some-fi-subscribers-double-during-their-pixel-3-sale/

Google Fi (formerly Project Fi) has been largely under the radar for the most part. Google often has sales and promotions bundled with Project Fi plans, and their latest one left many consumers fuming. Last Google Fi celebrated its fourth birthday by holding a one-day half off sale on the Pixel 3 and Pixel 3 XL. Many customers that purchased phones on financing plans are now being charged the full price of their devices.

Only customers who purchased Pixel 3 and 3 XL phones from Fi via the seem to be affected. It is unclear if other purchases are affected at this point. Several customers are claimed that they received no notification of the billing error. Several users have been charged as much as $500 for the Pixel 3 XL, and more for those that may have purchased multiple devices via the promo.