Hi, I've had a Liyu vinyl cutter for 4 years, bought from Signzworld. Never had a single problem until today. Now, I have areas where it looks as though the pressure of the blade, or depth of cut has reduced, meaning that when it comes to weeding, the vinyl just tears in certain areas. In some places on the vinyl, the blade does not even cut at all. Anyone had a similar problem? I have replaced both the blade and blade holder without any success.