Overcharging does not happen often. If you feel comfortable, screenshot your payment history page to confirm the overcharge. Sometimes, you may be charged twice, but one charge is left in your available funds which can be used for next month's plan.
@Lycaeum77 dial 611 from your phone and see if there is a credit balance for one of the charges. If there is, its better to leave it for the next 30 day payment cycle. Since it takes around 30 days tp get a refund. Stay safe.
@Lycaeum77 So the first payment was used to renew you plan and the other payment is sitting in your account fund balance? If yes, then that amount will be used to renew your plan on your next renewal date.