** Shares of Tuas TUA.AX fall 44.3% to A$3.46, their lowest level since March 2024
** Singapore's telco regulator suspends the review for a deal between Tuas unit Simba Telecom and Keppel's KPLM.SI M1
** Regulator says Simba may have been using radio frequency bands that it was not authorised to use
** Shares on track for worst day on record, if moves hold
** Stock down 55.9%, YTD, including movements in current session
(Reporting by Jasmeen Ara Shaikh in Bengaluru)
((Jasmeenaraislam.Shaikh@thomsonreuters.com;))