I am sorry you waited until you were so frustrated to make your first post since February. I wish you had asked for assistance when you first started having issues so someone could have helped you and alleviated the feelings you are having.
I understand you are frustrated - we have all been there at one time or another. But you haven't given me enough information to even begin to try to help. What speed and force are you using. Are you using a SB mat? Is the mat clean? Where are the designs from that you are cutting. What numbers are you using for offset and overcut. Have you done a machine reset just in case some setting was thrown off. Are you origin cutting or WYSIWYG?
HTV is some of the most difficult vinyl to cut and you will see many users having issues with it at times. It is not the machine, it is the HTV. Have you tried cutting it from the back side?
It is hard to figure out the problem when you are switching from material to material so I cannot tell what works and what doesn't. If you are getting a clean test cut, that is good. So now we need to look at what you are cutting, the mat, the blades etc. When you are using the mat, are you brayering the material to the mat so it is laying flat. One of the most common reasons for a design not to cut is that the material is not making a good contact with the mat.
Here is a conversation with someone having the same type of problem - at least with the circles.
viewtopic.php?f=8&t=5861&p=94945&hilit=cutting+circles#p94945The purchase of the machine does come with an hour of technical support and other than the fact that it is a holiday weekend, you can certainly email Sherri and request support to get you on track. She is on vacation (the first week off in years) but is checking her email. That might be something that would be beneficial to you - to have direct help rather than trying to google things on the internet which can be frustrating. Have you watched the videos posted on You Tube and this forum that go over the basics of the machine to be sure you are not missing something simple? Have you had difficulty from the beginning or is it just a hit and miss situation? Again, trying to get a clear picture of what is happening.
If you want to upload one of the problematic designs so someone can test cut it, please do so. I assume you are using the most updated version of the SCAL software? Are you on a Mac or a PC? The more information you can supply, the more we all can help. Although given that it is a holiday weekend, most users are not checking the forum.
The more information you can give, the more helpful we all can be. I would suggest you start with a machine reset, check all of your settings, and work with one material with a fresh blade and clean mat and see if you can get consistent cutting of just a basic design - for instance something from the SCAL library. Switching between materials makes it really difficult to problem solve - but we will do our best.