Yes - while we're looking into a complaint, you can deal with your customer as normal. And if you do something which might be relevant to the complaint, you should let us know.
It's very important that you tell us if you want to make a new offer - so we can consider whether that offer seems fair. And we'll put the offer to the consumer, so they can decide if they want to accept it.
We recommend that you wait until we've looked into the complaint before taking any legal action - like proceedings to recover a debt.
If you're planning on taking legal action, please let us know.