I’m not aware if this is correct for your circumstances but an empty montly statement sometimes relates to a product/service you may not be using.
For example, I use the ISA account, but I also receive an empty statement for the CFD account sent through,because I do not trade on the CFD platform.
Make sure the account numbers tally to the product/service you are trading.
Lastly, Trading212 will get back to you, have no fear about this. They are super busy right now with the current economic timing + the backlog of Transfers coming into their system. Wait a little longer and all will be answered for you.