Heads up for everyone, if you use your bank account to pay for Walmart MasterCard balance, the transaction would take about 5 business days at least to go through, and for your Walmart MasterCard to reflect the updates online.
I was almost maxed out with the credit limits, so I made a payment from my bank account to Walmart MasterCard account thinking the transaction would be done by next day. But I was surprised it took almost five business days for transaction to show in my Walmart MasterCard online account. I actually went over limit by $500 the very next day I made the payment. Luckily it was the end of my credit card period for the month, and so I wasn't charged $25 for going over credit card limit. At first I thought that since I have already maxed out my credit card limit, i won't be able to use my Walmart reward MasterCard at all, but I could still use it. The only thing is that whatever extra amount goes into over limit amount.
How it works is that by the end of the billing cycle, if there is any amount over limit, you would be charged $25. But if you managed to pay off some money until your balance is within or below your maximum credit limit, before your monthly bill is issued, then you would be saved from having to pay the over limit fees.