Immigrations just announced that you can set up appointments by telephone instead of standing in line all day and all night in order to renew your tourist visa, renew residency, start the residency process, ect. Lately, migrations has been a total quilombo with people in line for literally days in order to take care of immigration issues.
Call 5222-7117 between 8am-4pm.
Immigrations website: www.migraciones.gov.ar/
Here´s the link for the article in Clarín which discusses the changes: