So, our genuine Brother Toner (I buy genuine because of bad experiences with non-genuine) told us it was out of toner. I did the usual shake it etc and got about another 25 pages out of it til it told me it was completely empty and couldn't print another single page even if it tried.
I reset the toner counter manually on the printer and it's now done another 115 (ONE HUNDRED AND FIFTEEN!) pages and still printing.
Honestly the toner companies are lying to us. I could understand if it gave the warning about 100 pages before running out, but to flat out refuse to print and still have that much toner left is deceitful. It should be against the law. Not only is it ripping people off, but imagine all the toner that is going into bins and ruining the environment.
[rant over] <for now>
Have you spoken to your printer about how it has been behaving?