Hi All. I'd like to share my experience to date with this: On 13 Dec 2016 I parked at Battle rail station and paid using my mobile phone. I successfully paid but my phone would not reply to the 68680 SMS I was sent and had to reply to with my vehicle reg. When I returned I found a Penalty Notice quoting Rail Byelaw 14 for £100. My appeal with Indigo through their web based appeal system was rejected and I am now in the process of appealing through POPLA. I have been investigating why my phone would not reply to the 68680 SMS. I only had 7p credit on my phone and the 68680 SMS short code is classified as a premium rate number by O2, and is therefore excluded from my pre-paid phone bundle. The cost was more than 7p (I believe it to be 10p) so it would not send. The car park placard with payment instructions states that there is a 20p charge for using the service, which is added to the parking fee and is paid when you call the 0345 number. No where does it mention an additional fee for replying to the SMS. O2 have 68680 as operated by Mirada and listed as a premium rate gaming number. I have also spoken to OFCOM and they say because the charge is no more than 10p it is not classified as a premium rate number, and is therefore unregulated. This looks like an operator exploiting a loophole to me. The number is listed as premium rate, so is excluded from pre-paid packages, and because the charge is 10p, OFCOM say it is unregulated, therefore there is no need to display charges. If I had had more than 10p credit the SMS would have gone and I would most likely never have noticed the additional charge. To rub salt in the wound Indigo make a big play on their web site that there are no hidden charges. I have informed trading standards through the consumer advice phone line.