Can we do a walk in for extending the three months visa to a non immigrant visa if all paperwork is in order?

Hi all! We are on a 45 days exemption visa and need to extend by 30 days. However when we attempt this online and select “regular appointment” there are zero available dates for the following MONTHS. We were trying at IT Square Laksi. Is this normal? Or could there be a bug? The website only allows us to book the “express” and “super express” appointments which are extremely expensive. As of now we don’t see any other option than to go in person.. which probably means queuing for hours😵‍💫 Any advice on getting this extension done more efficiently?🙏🏽 thanks!