One-Page Checkout [Support Thread]

[spawnie69]

I am using The One-Page Checkout version number and release date: 1.0.5-beta1 (2016-09-xx)
on my 1.54 site on Responsive Sheffield Blue WWW.GELCANDLECOMPANY.COM. I've been having some customers tell me that they are unable to follow through the checkout and get a blank screen right after they enter c/c info info.
I tried placing an order on my desktop pc and noticed the CONFIRM button was displayed way on the far right which has been unable for some to see.
(see pic)
When some customers inform me of the trouble I inform that the button is at the far top right and they checkout successfully.

Is there any advice on how I can make the CONFIRM button appear in the center of the page making it more visible for desktop?
Mobile phones appear just fine.
Thanks for your input.