I recently purchased the window for my GE dryer door

I recently purchased the window for my GE dryer door. My tax rate is 3.9% and the GE online vendor software calculated it at 10.8%. I spent 2 hours talking to seven representatives and was given the runaround. There was never any resolution and I'm most concerned that their sales tax software vendor is providing an inaccurate product and no one that I spoke to assist me, they just passed me on.