When I make a call to GetOrders, the eBayPaymentStatus is PayPalPaymentInProcess for all the transactions which are paid via PayPal. Why is this happening?
There are a couple of reasons why the eBayPaymentStatus could be PayPalPaymentInProcess:
The payment from buyer to seller is in PayPal process, but has not yet been completed. It can take a few days for the process to be completed with instruments like echeck.
The seller has not setup the account with PayPal to receive payments. The seller needs to sign up with PayPal and confirm the email address in order to be able to receive payments. See the PayPal help page for more details.
The seller has enabled the account for Payment Review. The seller needs to go to the PayPal account and either accept all the payments or disable Payment Review.
Also, the seller needs to have a PayPal Premier or Business account to be able to receive payments for items sold. See the article Can I sell with a Personal account? for details.