Shares in mobile value-added mobile service providers plunged after China Mobile issued new rules to protect subscribers. The telecoms provider is also expected to take a hit, The Standard of Hong Kong reported. China Mobile will now send subscribers two notices before charging subscription fees, following a directive by the Ministry of Information Industry. Customers will also get free trial periods of up to 41 days. The company also plans to cancel numbers that are inactive for four months. Early in its history, China Mobile offered generous terms to value-added providers but with revenues from those services growing to 20% of the company's total, the country's biggest mobile operator has started looking at offering its own.