Avoid in-store pickups when billing address is incorrect due to iPhone autofill bug

There is a bug in the iPhone autofill that sets the country to Cote d’Ivoire instead of Germany for iPhones set to use the German language.

We are operating a shop in Germany. I’ve removed Cote d’Ivoire from the countries we ship to, but we still get customers who select in-store pick up and have their billing address set to Cote d’Ivoire. We want to avoid this because it complicates issues with tax reporting.

According to the post below, it’s not possible to restrict customers based on billing address. Is there any other workaround I could use to avoid in-store pickups when the billing address is set to a certain country?