I've tried for 2 people over the last month to report online for Jomtien. You cannot even get to the pending stage anymore. You simply get the contact immigration message that you would, if you had not done a 90 day report. Ones been here reporting 8 years, the other 11 years.
I don't believe there is any walk in service. You apply online, then if it is agreed, you show up with the paperwork, turn it in and go back the next day and collect your passport/visa.
The only issue is that nobody has yet confirmed if Singapore will actually issue a visa to SA passport holders.
Somebody renting a condo here last year went from Pattaya. If I remember it was 2800 baht. No idea what it included but I know he had to wait a while as they never went everyday. It's pretty quiet with people now so I doubt they are busy to go everyday anyway.
I've no idea who the agency was other than they were Russian.
4 consecutive visa exempts. If you've extended them, that's an 8 month stay. Going for a visa brings that too nearly a year. Might be an interesting result. Let us know how it go's.