cant make a payment credit limit is off

Tried to make a payment my bill is due tomorrow, but the site says I'm past due already its not asking for the min payment but the whole amount from last month and my credit limit went down and  the paper bill and on line bill from this month does not match they told me it was an error and they are updateing thier system , I wanted to set my payment for the following day because I get paid sent to collections where I was hung up on, still on hold once again this is my 3rd time I dont want a late fee and I want to know what's going on with my acct.