So you weren't refused then. You didn't officially submit the TM30 at that office and went to another with the required documents. If you turn up with all documents required at the Chonburi office there should be no problem as far as I understand it.
You need what is mentioned above....THEN you need to copy the TM30 slip you receive and have another photo for the extension.....(Total 2 photos). If going in morning go earlyish....if afternoon they open after lunch at 13:00. Allow min 3 hours.
It is for all foreigners in Thailand when making an extension. A. Hotel stay......They contact Hotel (who should have registered you)...or B. You are in short stay and not a hotel....they contact Landlord or Owner......or C. Long Term stay with a contract. You as the Housmaster or Possessor of the property lodge it yourself (recommended).
It is no problem. May be a fine or may not be...depends on the day. Complete and lodge the TM30 when you are there and then apply for the extension. As a long term renter you are responsible to lodge the TM 30 yourself, not the Landlord. You signed a lease, you are now the Housemaster or Possessor of the property. I have not heard of anyone being refused an extension.....but you never know....