Amid recent reports of Verizon Wireless customers getting dinged on their bills for going over their monthly data allotments, some of these subscribers say they are going over their data limits because Verizon stopped sending them overage alerts.

The Cleveland Plain Dealer has been highlighting the stories of Verizon customers who say they stopped receiving text alerts from the carrier warning them that they were was approaching their monthly limits.

One woman says her bill is normally $130 a month, but this month’s bill came to $838 — including $700 in overage fees. She called Verizon and the company said it had been sending her text alerts, alerts she swore she never received until the one that said her payment was late.

Another subscriber who faces a $1,700 bill tells the Plain Dealer that she’d previously relied on the automated overage warnings to keep her from going over her limit, but claims she stopped receiving them.

A woman in Iowa says her family somehow managed to go through a month’s worth of data in just a few days, but the only alerts they get are when it’s too late.

Another Verizon customer says he’s been smacked with fees because Verizon stopped alerting him about possible overages before he hits 90% of his monthly allocation.

“I no longer get the 75% notification,” he told the Plain Dealer. “I relied very heavily on the warnings because then I could manage my usage.”

That’s because Verizon does not automatically alert users at 75%. A rep for the company tells Consumerist that users can opt in to receiving alerts at this threshold, but the automatic alert doesn’t kick in until you reach 90% of your monthly allotment.

“All Verizon customers receive a text alert on their device when they’ve used 90% of their plan data in a month and then again when they’ve hit 100% (which indicates they’ve gone over),” the rep told Consumerist. “In addition, customers can also better manage their data use by opting in to a 50% alert and a 75% alert.”

He also pointed out that the New Verizon Plan has a Safety Mode for all data bucket sizes, a free feature that kicks in once a customer hits their data limits. If it’s enabled, it means you won’t get an overage — your data speeds will just slow to 128 kbps once you’ve exceeded your plan limit.

We checked in with the other three major carriers to clarify their policies on data overage alerts as well, and it seems that Verizon is the only one that requires users to opt in at lower threshholds:

T-Mobile: The company confirmed that there are no data alerts — because T-Mobile got rid of overage fees entirely for all post-paid customers in 2014.

AT&T: AT&T automatically sends a courtesy text message and email alert when you reach 75%, 90%, and 100% of the data included in your plan, a company spokesperson told Consumerist.

Sprint: Sprint customers receive notifications at 75%, 90%, and 100% of data bucket usage, a company spokeswoman confirmed to Consumerist. There’s also the option of the Better Choice Plan, where customers can choose to get unlimited data at 2G speeds after 100% data usage/after exhausting their monthly allotment.

Want more consumer news? Visit our parent organization, Consumer Reports, for the latest on scams, recalls, and other consumer issues.