Brazilian regulators have suspended sales of new cellphone plans by three big carriers because of poor service and customer complaints.

Brazilian phone regulator Anatel says in a statement that carriers Oi, TIM and Claro cannot make new sales starting Monday in a varying number of states. Together, the companies represent about 70 percent of Brazil's mobile phone market.

Sales for TIM Participacoes SA are halted in 19 states. It is the local unit of Telecom Italia SpA. Oi, which is Telemar Norte Leste SA, has sales stopped in five states. America Movil SA's Brazilian unit Claro SA has sales suspended in three states.

The companies have 30 days to present investment plans to regulators showing how they'll improve service. Only after plans are approved can sales resume.