The banking aspirations of listed payments provider iSignthis Ltd are up in the air after regulators on Wednesday announced a suspension of trading in the company's ASX-listed shares.In a filing to the market before trading opened, the ASX revealed iSignthis scrip would be suspended indefinitely as it and the Australian Securities and Investment Commission examined undisclosed "issues" relating to the company.The suspension is a major blow to the company as it coincides with the Australian Prudential Regulation Authority considering its application to secure a special banking licence that would allow it to expand its domestic payments services business.Founder and CEO John Karantzis told Banking Day in August that he was positioning iSignthis as a direct competitor to PayPal Australia.If the licence application is approved by APRA, iSignthis would assume the status of an approved deposit taking institution, with the only restriction being that it could not pay interest on funds held in customers' accounts.However, the trading suspension and heightened regulatory examination of the company's affairs have cast doubt on the company's near-term prospects of obtaining the ADI licence. The ASX did not specify the types of issues it was examining within the company but cited the recent volatile trading of the company's shares among the reasons for imposing the suspension."In consultation with the Australian Securities and Investments Commission ('ASIC') and having regard to the recent volatility in its share price, ASX has determined that it is appropriate to suspend trading in the shares of iSignthis Ltd ('ISX') with immediate effect under Listing Rule 17.3, pending the outcome of enquiries to be made by ASIC and ASX into a number of issues concerning ISX," the ASX said."The securities will remain suspended until further notice."The company's scrip last traded at A$1.07, but were valued as much as $1.76 last month before a report published by corporate governance firm, Ownership Matters, questioned the governance record of the business.Since the release of the report on 10 September the share price has traded as low as 69 cents.The OM report alleged that iSignthis had provided limited disclosure on what drove a revenue surge in 2018 that allowed Karantzis and other executives to exercise rights to shares in the company.Karantzis defended the 2018 revenue disclosures, saying they were carefully assessed by the company's auditors.The share price has also been dented by news of legal action brought against Karantzis by a former investor in the company who is claiming an entitlement to shares in the company that he never received.