Thank you for reaching out to us in our community and welcome, sorry to hear your order for an iPhone 12 has been parked, This happens when an order is placed online, and it needs to go through extra checks. Unlike when you do this on the phone, an agent is able to provide the information there and then. If the team needs more information from you, they would usually contact you in 24-72 hours, if not the order would be released. The other reason why this may be parked would be because the credit check had failed.
I advise giving us a call on 0345 600 0789 and a member of the team, will be able to look into this for you?