@Razz while H C Andersen is not wrong, there's a much quicker and easier way to deal with this. We know a notice of rejection was issued on 6 February, because the TFL website says so:

In the circumstances, the quickest and easiest way to deal with this is to file an out of time appeal with London Tribunals.
The first step is to make a subject access request to dpo@tfl.gov.uk asking for a copy of the notice of rejection to be emailed to you, remember you will need to attach either a copy of your ID or proof of address. You don't need to get the response before you can file an appeal, but it's best to get the ball rolling just in case you need it later.
In the meantime I'll drop you a PM in case you'd like me to help you with the out of time application to the tribunal. Assuming the tribunal agrees to consider the case, the email from the tribunal confirming that your appeal will be heard has the effect of cancelling the charge certificate, and this saves you having to faff about with TEC, or going to have forms sworn, or waiting for weeks and weeks for TEC to process them and then for TFL to refer the case to the tribunal.