Nigeria, April 2 -- A feud between Nigerian banks and MTN left millions of subscribers unable to recharge their phones using the USSD services on Friday, after banks shut off the telecoms firm over fees charged for the service.

MTN advised its subscribers to seek alternative means of recharging their phones without informing them what the problem was.

"Dear Customer, our bank recharge channels are currently unavailable. Kindly recharge using physical cards. We apologise for the inconvenience. Thank you," one message read.

Another read: "Please be informed that some of MyCustomers may not be able to purchase airtime and data recharges via banks including MOD and myMTN App. Please pacify MyCustomers and educate them to use MTNTopit, MoMo...