How should I proceed as the online portal is also warning me that the fee is about to increase to £195.00
Worry not ! Letters from councils are going astray more and more often.
ALl you do is now wait for the Charge Certificate to arrive, (the £195),
but do not pay it, and at the end of the period given in it to make payment, after about a week, you phone the Traffic Enforcement Centre, and ask whether the PCN has been registered. When the council register the debt, they will send out an Order for Recovery. However, as you have had one document fail to arrive, you mustn't miss this final OfR stage, so by contacting TEC at weekly intervals, until the PCN is registered, you can then, even if the OfR has not arrived, submit a Statutory Declaration (Form PE3) and the matter will be reset to the Notice to Owner stage, (reps submitted). On the PE3 you tick the box for "submitted reps but got no reply".
https://www.gov.uk/government/publications/form-pe3-challenge-an-unpaid-penalty-charge-noticeI can hear you saying, "but what if I don't get the Charge Certificate ?". Answer to that is you'll have to contact the council, but if the amount is now showing £195 it would seem they are about to send it out, or have already done so.
It is now plainly obvious that the process relying on Royal Mail 1st Class post is no longer viable with the chaos in Royal Mail. The law needs to be changed urgently to mandate tracked delivery. This would cost the councils slightly more money, but they're making millions already so could afford it.