Paypal付款后上传到Dropbox

I'm trying to find a solution for customers to upload files to my dropbox after completing a payment in Paypal. Basically I'm looking for a solution to collect payments and files from customers.

What I have so far (I have a so-so working version)

1. user fills a PHP form with info & files
2. user previews the info
3. info submitted, user directed to Paypal
4. Paypal returns after payment to my thank you page and files are uploaded

However this doesn't really work. The dropbox upload doesn't work for whatever reason even when the payment goes through.

Instead of debugging this and wasting time I was thinking there might be a ready made or an easier solution than building it from scratch.

The minimum I would need to happen

1. I agree on the price over email for example
2. I send a link to the user to the page where they can upload files
3. They complete payment in Paypal
4. Files go to dropbox

Would anyone know if there is a service that provides this or an easier way or do I just need to continue building a tool like this?

Have you checked Jotform?
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