AGE VERIFICATION IN SOUTH KOREA

hi im a foreigner currently staying in south korea and i want to download call of duty but age verification pops up and everytime i fill up the form it always say that make sure that your information is correctly blah blah blah but i type my name correctly and change my birthday cause under 19 but stills won’t verify my age and always say incorrect even though its correct I would really appreciate some help :)) thanks