Most cellphone and tablet users can purchase digital goods and charge them to their monthly bill or prepaid phone account, but buyers may not get the protections they need if something goes wrong with the transaction, a new report says.

According to an analysis by Consumers Union, the protections that consumers receive vary depending on their wireless carrier's policies and what's in their cellphone contract. 

"We found that consumer rights can vary widely between wireless carriers, and the protections carriers claim to provide are often nowhere to be found in consumer contracts," said Michelle Jun, senior attorney for Consumers Union, the nonprofit advocacy branch of Consumer Reports.