You may call our Individual Income Tax Helpline at 1800-3568300 during our office hours from 8am to 5pm from Monday to Friday; and from 8am to 1pm on Saturdays or email us. If the update is a change in name, please send or attach a copy of your NRIC, Deed Poll or Passport. You can also write to us at:
Inland Revenue Authority of Singapore
55 Newton Road
Revenue House
Singapore 307987
http://www.iras.gov.sg/ESVPortal/iit/iit-se-a1.1.20+penalties+for+late+or+non-filing+of+it+forms.asp
↑What are the penalties for late or non-filing of income tax form
http://www.iras.gov.sg/ESVPortal/iit/iit-enf-v.a.1+penalities+for+late+or+non+payment.asp
↑What are the penalties for late or non-payment?