Welcome to the community.
If your May's statement period END meter reads where estimated then your June opening reads should be the same.
Best proceed to contact PP's members service team via wattBot.
Open the APP - open help - open ask wattBot - then type "Message the Team" and post your question.
Response will arrive within 2 days or sooner back in bot space by one of PP's nice team.
I guess you know you can send meter reads (frequently every 24 hours) on OUR statement date which means bills are not estimated as the statement is emailed the follow day. Sorry in advance if you new this.
All the best