Complex sentence: To circumvent the problem, Malaysian Immigration officers in Tanjong Pagar did not stamp passports, instead scanning them into a computer system and providing a stamped embarkation/disembarkation card, to be retained until leaving Malaysia.
Split into simpler sentences: To circumvent the problem, Malaysian Immigration officers in Tanjong Pagar do not stamp on the passports of passengers. Instead, passport details are scanned into a computer system and a stamped embarkation/disembarkation card is provided for each foreign visitor, which must be retained until leaving Malaysia.