online credit card payments?

I seriously doubt, as you assumed, that the company is ‘holding off posting.’ In fact, all online payments are processed electronically.

If the site told you that the payment would post on the 19th for a payment made on the 16th (which sounds reasonable) it may not show that payment online for another few days (depending on your CC company) but rest assured that the payment was posted (so long as funds were available from your bank.)

To double check, you can always call the company and have them check the back end (as the consumer side of the website probably takes longer to refresh.)

Finally, I might suggest using your bank’s online bill-pay as opposed to the individual credit card company’s site. This way, if there is ever a problem, your bank would normally assume responsibility. Hope this helps!