I looked at your website and I think the site overall looks pretty good. Here are some of my thoughts on areas you could improve:
1. The slider on the homepage goes a little to fast, try slowing down the images so people have time to read the text and look at the image.
2. On the desktop the layout is nice, but when I viewed it on a tablet the text overlapped each other on some places.
3. In my opinion, there is too much going on with the Credit Card Processing page. There are three columns, Proven Results, the actual main text, and the side bar with the different widgets. When I first landed on the page it was a little overwhelming with all the text and I was unsure what I should be reading first. It looks like you did something similar on other pages as well. I think it make the pages look crowded and you could potentially cause people to get overwhelmed and leave.
4. Would it be possible to turn your Proven Results page into more of a case study page? Instead of using general terms like "a retail store" you could use the stores name, with their permission. It is so much more compelling to see an actual store name, maybe even a picture of the owner next to it. It would make people feel more comfortable about using your services.
5. One last small item, I would have the numbers for your phone number as well if you want to have the letters. Many smart phones don't have the letters next to the numbers, so it would be extra effort for people to figure out how to call you. Also, if you click on the number on a desktop it brings you to an error page, maybe have it link to a page that says this feature only works on mobile phones or something like that.
I hope this helps!