A consumer protection group sought THB22 billion ($687 million) in damages from AIS, True and dtac in class action lawsuits relating to overcharging for calls.

The Foundation for Consumers claimed the country’s three major mobile operators had continued to round up customers’ call times despite an order from the National Broadcasting and Telecommunications Commission (NBTC) in May 2016 requiring them to adopt per-second billing, Bangkok Post reported.

Saree Ongsomwang, secretary general of the Foundation for Consumers, said despite efforts to encourage the operators to comply with the NBTC requirement customers “have still been exploited by the operators” so it opted to take legal action, the newspaper stated.

When the foundation was preparing the lawsuit in January 2017, Saree said the operators’ refusal to comply had cost subscribers an estimated THB18 billion, or about THB40 per user a day, between May and December 2016, The Nation reported at the time.

Also in January 2017, NBTC backtracked on the earlier order, requiring operators to offer per-second billing on half their mobile plans rather than all tariffs as originally stated.

Thailand, a country with a population of about 70 million, has nearly 91 million mobile connections, the latest data from GSMA Intelligence showed.