@Seven *********
, just so you know you need to use an address IN the area where the immigration office is located to get an extension. Meaning you can't use the Pattaya immigration office to get an extension using a bangkok address.
Also as people pointed out in Jomtien if you're staying at a private residence your land lord OR you needed to file a TM.30 form within 24 hours of you taking up residence there. OR you're gonna get a 1600baht fine for failure to have done it.
I'd say just go get your extension in Bangkok out at the government complex on Chaengwattana Road. The immigration office there doesn't care at all if you or your land lord ever filed a TM.30 form or not.