The office is at the Swampy airport. But , since you are OUT of TH , I would suggest you once coming down here on a T visa and meet officials personally and clear all obfuscations.
If you have a 60 days SETV in TH then you are eligible for VOA in SG , provided you show a return ticket to India. IND , TH and SG have a tripartite travel agreement. Read about it.
Edit: If you are on a Non B in TH, then you can simply go to SG embassy and apply there.
If you are in SG , you can get 15 days VOA to TH which can be extended to 7 more days for 1900B. If you want to apply for 60days SETV, India is the ONLY PLACE.
1. Thai immi. is strict with back to back border runs. Apprently they run their own fiefdom with a stupod rule of 180 days allowance on T visa per calendar year , which is NON EXISTANT on papers. She has to wait for a sometime before she can come in on a T visa issued from TH consulate in PH.
2.She can always go home , no problem.
3. No other country will care about any sort of negative stamp given by TH immigration.
Next time she should have 20K baht as funds , hotel booking and return ticket to make an idellible mark as a real TOURIST.