I'm not familiar with this aspect - how do cellular services store and make use of billing information, as opposed to traditional phone services?

Most cellular systems still write billing tapes and send them to a clearing house for proccessing. It may take 2 or 3 days before a bill is updated. Thats not including that it takes sometimes up to a month before your roaming charges are recorded from all of the other cellular carriers. Some carriers have realtime billing but it still doesn't take into account roaming.

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If cellular customers start getting sales calls from a company that received a list from a cellular carrier, the cellular carrier is obligated to refund the customers bill for those calls if the customer complains becuase the customer pays for calls comming or going.

Is this obligation incurred by the contract between the customer and the cellular service, by statute, or otherwise? Contracts can always be broken, and passing laws to guard the guardians generally amounts to having the fox guard the henhouse...

This obligation is uncurred mostly by the fact that cellular carriers HATE to loose customers. If refunding a few min. of air-time helps keep a customer then they will. Unlike the phone company, a threat to discontinue service with a cellular carrier works well in getting your way. Dr0id