。
My phone was cut off for overdue payments.
Literal
Fee late-payment [reason-で] phone [object-を] was-stopped.
延滞 (late payment/arrears) is a precise piece of financial vocabulary — it emphasizes the lateness of payment, in contrast to its near-neighbor 滞納, which emphasizes outright failure to pay. で marks the reason. 止められた is the adversative passive of 止める — something unpleasant was done to the speaker by an implied agent (the phone company).