Unactive bin button, can’t delete photos from ICloud Photos

Can anyone please help in such situation : I can not delete photos from ICloud Photos because the bin button is inactive. It is only possible to download them. There is also written that iCloud Photos has been disabled and I have 28 days to make sure I have a copy. But I don’t need it, I want to delete everything completely because I am giving this phone away and don’t want anyone to be able to restore my data. Please help, this is very urgent.