bigmoe said "When I buy something at Walmart on my credit card it shows up within minutes when I check my credit card account online. Two different companies. Instant! "
When you pay with your credit card it gets sent to your credit card company who instantly approved the transaction. The amount comes off your available balance but does not actually post to your account for 24 to 48 hours. That's why your online account will show "pending purchase" and "approved purchase".
Doing a payment on your credit card from your bank account is a slightly different thing. There is not an instant notification sent to your credit card company from your bank-that takes 24 to 48 hours.
If I do some bill payments from my bank account now-any time before midnight tonight-my credit card payment will show up on my credit card after midnight tomorrow night. (My card is not affiliated with my bank.) If I pay my cell phone bill at the same time, my cell provider will email me at noon tomorrow saying thank you for the payment. If I pay those same bills any time on Friday, my credit card company will not have the payment showing up until after midnight Monday night. My cell provider would acknowledge the payment at at noon Monday.
If you paid your card more than 48 hours ago and it still is not showing up on your card, that seems like very slow service between the 2 financial institutions.