WordPress messes up my form code when using the Visual View tab

I have a simple payment button on our homepage with a pull-down menu to choose a product. But the WordPress editor keeps screwing up this block of code by moving a couple important tags, whenever I use the visual editor tab. It is very frustrating, as I have to replace the button code with every single edit we make to the page.

Here are some screenshots to see what it is doing…

Correct code:
http://www.screencast.com/t/XmPmuR0ff

Jumbled code:
http://www.screencast.com/t/i3RP3uetKA4l

Please help me fix this issue.

Thank you!!

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