If you have been admitted as a solicitor and your name is still on the roll, but you do not have a practising certificate, then you are not qualified to act as a solicitor under section 21 of the Solicitors Act 1974. Furthermore you commit an offence if you act as a solicitor or pretend to be one.
You might think that having passed the examinations, completed your training contract and been admitted, it is a bit harsh that you still have to pay for an unnecessary practising certificate for the privilege of calling yourself a solicitor. However, that is clearly the law. But if you cannot call yourself a solicitor, what can you call yourself?