Assalamualaikum wa rahmatullah, May Allah reward you and give you ikhlas ya Sheikh, Just recieved an electricity bill reminding me that I forgot to pay this month. I have to pay a small late payment fee. I called them but they didn't take it back, is this riba? Jazakallah kheir

Ustadh AbdulAziz al-Haqqan

Yes, therefore make sure u are never late again.