Paytm parent One97 Communications' shares hit a fresh low on Monday after the RBI barred the company's payments bank - Paytm Payments Bank - from opening new accounts citing "material supervisory concerns".Paytm shares fell as much as 13.3 percent to an all-time low of Rs 672.1 on BSE, a discount of 68.7 percent below its issue price of Rs 2,150. Prior to Monday's fall, the stock had hit an all-time low of Rs 728.5 on March 8.Paytm Payments Bank said it is taking immediate actions to comply with the RBI's direction, and that its existing customers can continue to operate banking and digital payments services without interruption.This is the third time One97's payments banking unit is facing action from the banking regulator since its inception in May 2017.Market expert Prakash Diwan said he was not surprised by the news on Paytm, which was the first few fintech platforms to move into a payment bank in a "fairly hurried" move."But the kind of mass participation that you have in the Paytm platform is definitely something which was always rolled to some sort of gaps in terms of compliance on particularly KYC... The way the IT platform could kind of corroborate all that documentation that was coming from all parts of the country in especially a lot of areas very new to banking," he said.Diwan sees more downside in the Paytm stock. "Nobody is going to stick their necks out and buy into it, especially when there's such a big area of concern that needs to be repaired... The valuation will definitely start to look even more expensive than it did at the time of the IPO," he said. Macquarie maintained an 'underperform' rating on Paytm and its target price at Rs 700. The brokerage expects the RBI's action to have a significant impact on the company's brand and customer loyalty.Many experts have been sceptical about new-age companies such as Paytm. In January, market veteran Shankar Sharma told CNBC-TV18 one should not be surprised if shares of new-age companies fall 80-90 percent by the end of 2022.Paytm shares have suffered a series of losses since listing on stock exchanges BSE and NSE in mid-November at a discount of around nine percent to the issue price. Its IPO - the biggest of all time in India - saw an overall booking of 1.9 times the shares on offer, failing to win the kind of investor interest enjoyed by most IPOs in 2021.