T-Mobile is raising several monthly fees from September 28, pushing up bills for millions of mobile and home internet customers in the United States.

The per-line “recovery fee” rises from $3.49 to $3.99, while the telecom fee on voice-only lines increases from $1.40 to $1.60. Home internet customers will see their recovery fee climb from $2.25 to $2.60 a month, and the charges appear as small line items that many customers only notice when the total rises.

The increases, first reported by The Consumerist, apply automatically, meaning many customers will notice higher bills without taking any action or changing their plans.

T-Mobile has not given a detailed public explanation for the rises, which come as carriers face higher network and operating costs across the industry.

Customer reaction online was swift and angry, with many subscribers complaining that small recurring fees keep creeping up. For a household with several lines, the changes could add more than $10 to the monthly bill.