Student or Learner
Which is correct
shopping at eBay.com OR shopping on eBay.com OR shopping with eBay
You got a new payment at PayPal.com. OR You got a new payment on PayPal.com.
I think that you can say all of them.
Shopping at ebay.com (treating ebay as a conventional store, like shopping at Harrods)
Shopping on ebay.com (treating ebay as a website, like "I saw it on ebay")
Shopping with ebay.com (treating ebay as a facillitator of your shopping)
Likewise, at paypal.com is like at a bank, and on ebay.com is treating paypal as a site of information, get a new payment via ebay.com, from ebay.com, and using ebay.com are all also possible in my humble teacher's opinion.