Forget about the penalty charge for now, you need to deal with the Order for Recovery. The first thing you must do is will in form PE3 by ticking the box to say you didn't get the original PCN, but do not sign the form.
You will need to make an appointment at your local county court or magistrates' court to sign the form in front of either a court officer or a justice of the peace. Once they've watched you sign the form, they will sign and stamp it, you can then scan or photograph it an email it to tec@justice.gov.uk
This will result in the order for recovery, the charge certificate and the original pcn being cancelled. The council will then reset the PCN to the initial stage and you can then make representations in the normal way.
If for whatever reason you can't get the PE3 form sworn in court over the next few days, then as an alternative you can go to any high street solicitor, they normally charge around £10 to do this.