combining 3 if statements into one

[amritkishan29]

please help me..
i programmed cell k13 to remind me "billing due" if i have paid my bills or not using today() function..if we paid, we need to type "paid" into n13 and it should clear the text in k 13..if we haven't yet paid we need to type "not paid" and it should say "Billing due"
these are my three formulas..but they aren't clearing the cell..=IF(K13 *less than TODAY()+3,"BILLING DUE","")&IF(N13="PAID","","")&IF(N13="NOT PAID","BILLING DUE","")

*the less than symbol deletes my texts after the symbol in this thread for no reason so thats why i've typed it in
thanks

 

[SteveO59L]

=if(k13=today()+3,"Billing Due",if(n13="Paid","",if(n13="Not Paid","Billing Due","")))

 

[amritkishan29]

that works man, thanks! :D but i need another little help..i need it to say "Billing due" if the paid/not paid cell is empty when its due time to pay! what should i do for that?

 

[amritkishan29]

=if(k13=today()+3,"Billing Due",if(n13="Paid","",if(n13="Not Paid","Billing Due","")))

if i put this formula, the first part where the date is compared to the current date isn't working