Nextel, I shake my fist at you

My big complaint with Nextel has always been its bill turn-around time. They issue the statements mid-month, and they're actually due at the end of the month. This means that by the time you receive a statement in the mail, you have about 5 days before it's due. I think this policy was started to encourage people to have their bills paid automatically and to pay online.

I do pay online, and I haven't really had any trouble with it until today. I got my Nextel statement on Thursday. I figured it would be due around Tuesday, so I opened it Sunday evening (having been busy this weekend), and discovered that it was due that day. I tried to pay online, and the site is undergoing maintenance, so I can't. Frustrated and frantic about late fees and credit ratings, I rifled through the bill looking for a late fees policy and noticed that one won't be charged for another 15 days.

Why don't they just say the bill is due on March 15 like a normal company, rather than having this extra grace period? Will this affect my credit? What affects credit ratings in the first place? Why wasn't I taught these things along with the rest of account management when I was in second grade?

Grr...