With no palpable abatement in pesky calls and SMSes despite several attempts to control the menace, telecom regulator Trai on Thursday mandated financial penalties on telecom service providers whose networks are used for the unwanted communication by marketing companies. The Telecom Regulatory Authority of India also warned that phone connections of banks, insurance firms and builders will be blacklisted if the mandated rules on unsolicited calls are violated by them, or their representatives.