Trying to use pay pal to pay for my order on e bay but it wont go through

Thanks you for writing in regard to your payment concern. As you are unable to pay for the item youve purchased using PayPal. Let me help you with this.
First, I want to know the error message that you are getting so we can assist you further.
Now, if the error message you are getting is "Unable to process payment. Please try again later" or something like that, the best thing that you can do is to do a manual payment thru PayPal.

But first, you need to contact your seller and ask for a manual invoice and his correct PayPal email address.
Here is how you can get the sellers contact details:

Here are the steps to have the member's phone number emailed to you:
TO REQUEST THE MEMBER'S CONTACT INFORMATION:
1. Click the "Advanced Search" link at the top of any eBay page.
2. Click the "Find Contact Information" link located to the left of the page.
3. On the "Find Contact Information" page, enter in the User ID of the member you wish to find and the Item number of the item you are trading with the member.
Please be reminded that at the same time, we'll also send your contact information to your trading partner for fairness sake.
Once you have the invoice and his correct PayPal email address, you may then pay the item manually thru PayPal.
Here are the steps:

As a work around, you can just send a manual payment to your seller's correct PayPal email address by using the "Send Money" tab from the PayPal site.

The good news here is you are still covered by the Buyer Protection Programme.

Here's how:
1. Log in to your PayPal account.
2. Click the "Send Money" tab.
3. Choose "Send Money Online".
4. Under "Payments made mainly to purchase goods or services", select "eBay Items" or "Goods".
5. Then hit the "Continue" button.
Hope I was able to cover everything to resolve your concer.