If you are using our digital-delivery feature to provide file downloads, send stored/generated codes, or redirect buyers to a premium-content URL, then those transactions would be marked as sales for digital goods. If you have enabled Shipping for any product, then those transactions would be marked as sales for tangible goods. If you are not using any of those features, then those orders would be for neither tangible goods nor digital goods. The only documentation we can provide would be your E-junkie Transaction Log, available from your Seller Admin.
We are not PayPal and can only guess at their motivations, but we might speculate that the fact you are taking money without seeming to provide any tangible nor digital "product" of value in return may raise a red flag with their auditors. If you are only using E-junkie to take orders for intangible services (such as SEO), paid for via PayPal and subsequently rendered online, then PayPal may be seeking proof that you have actually provided the services paid for, to establish that you aren't using your online store to launder money or run some sort of scam.
You may need to ask your past clientele to provide written letters, accounts-payable statements, etc. documenting the services they paid you to perform. There's really no document we could provide that would prove you have actually provided the services you are selling, so that's a matter of your own business recordkeeping practices.
It's dismaying to hear your money is frozen, but that is one of the risks of carrying a balance with PayPal. They are not a bank and thus not subject to banking regulations nor covered by Federal deposit insurance. They can suspend and have suspended accounts for any reason they deem fit. Personally, back when I was receiving sizable amounts via PayPal, I'd make weekly withdrawals to a real bank account. You might want to Google "paypal arbitration" to see what you're facing.