Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Frustrated user!

I have two P35 staplers - one is about 7 years old, the other is 5 years old. The problem lately is that none of the 356 model staples are working in either stapler for an extended period of time. The first 50 or so staples work, but then they begin to fail in puncturing the cardboard. I've tried spraying the moving parts of the P35's with silicone, and sprayed the sleeve of staples after inserting them in the P35- to no avail. It's very frustrating to have a deadline for making cardboard boxes and not have either P35 working with the 356 staples. I've tried 3 different boxes of 356 staples with the same consistent failure for each box. The staples won't fold over and close even if they puncture with great difficulty. Bummer!!