Yes, RSM can check your TOEFL, IELTS or Cambridge results online. However, the RSM Admissions Office can only do this if you upload a copy of your score report in your application:
TOEFL scores can be verified online. Therefore you should request the tests center to send your score report to RSM. The institutional code of RSM is 0798 and for Erasmus University 7199 (you can use either). Scores are verifiable for 2 years.
IELTS scores are verified online using the TRF code marked on the score report. Scores are verifiable for 3 years.
Cambridge results taken after 2005 can be verified online.
Note: it is sufficient to upload your score report and follow the instructions mentioned above. It is not needed for TOEFL, IELTS or Cambridge to send us your English certificate by postal mail.