I am trying to upgrade but it won't accept it!

It seems you have duplicate threads for this issue:

https://www.jotform.com/answers/1109850-I-am-trying-to-upgrade-but-it-won-t-accept-it-

If you wouldn't mind following up there, we will be happy to assist you further.

New response receivedI upgraded my credit card, which was expired.
I am still getting this message:
Unable to switch subscription. Please try again by clicking the button below.
If the problem persists please get in contact with our support team. Sorry for the inconvenience.
HELP!
...

Use the UPGRADE button bellow the selected plan to upgrade to that plan.

You can do this in your my account billing section or use this direct link https://www.jotform.com/myaccount/billing

When you click the Upgrade button, the upgrade payment screen will pop out.

Set the payment schedule and payment method and click on the green Upgrade button at the lower right of the pop out screen.

screenshot:

 

You will be able to upgrade the subscription after completing the payments.

Let us know if you are still not able to upgrade using the steps I described.

 

New response receivedSame thing:
Unable to switch subscription. Please try again by clicking the button below.
If the problem persists please get in contact with our support team. Sorry for the inconvenience.
CAN I CALL SOMEONE AND DO THIS OVER THE PHONE??????????????????????????
...

We do not currently offer phone based support.  Would you mind providing a screenshot of what you are seeing?  Here is how to include it in your forum post:

https://www.jotform.com/answers/414264-How-to-include-screenshot-image-in-the-support-forum

And here is the thread to add it to:

https://www.jotform.com/answers/1109857

 

New response receivedTHIS IS WHAT I AM SEEING!!!!! HELP ME PLEASE!
Unable to switch subscription. Please try again by clicking the button below.
If the problem persists please get in contact with our support team. Sorry for the inconvenience.
Retry
...

There are a few things you can try.  A different web browser, Chrome of FireFox tend to work best.  A different card for payment in case there is some unforeseen issue with your current card.  Or you can try a different payment method like PayPal.  PayPal accounts are very easy to set up.