If you have an Internet/phone/cable bundle, there’s a chance that your modem has a battery backup that would allow you to use the phone for several hours during a power outage. But not all Verizon FiOS customers know that it’s their responsibility to maintain that battery and replace it if necessary.

KDKA-TV in Pittsburgh recently looked into FiOS customer complaints about the batteries — and about having to go out-of-pocket to replace them when they fail.

After noticing the red light on his FiOS modem, one customer called to see about getting the battery replaced.

“[Verizon said] your battery is only warranted for one year,” he tells KDKA. “It’s up to you.”

A rep for Verizon confirms this, and claims that it tells customers about the one-year warranty limit when they get the modem. The rep said that asking Verizon to pay for a battery replacement is like asking the power company to pay for the batteries in your flashlight.

“The backup power is something that is really just a customer preference,” explains the rep.

KDKA says the 7-amp battery costs around $44 plus tax at retail. One local store says it gets around 10 people a day looking for replacement batteries.

But at least Verizon provides FiOS customers with a backup battery. In February, Comcast began making the batteries optional, charging $35.95 plus $5.95 in shipping for each battery requested by the customer.

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