Surat Thani Immigration - of which the Samui office is a branch - has an well working online system for TM30. The landlord or hotel will get an spread-sheet file (.xls) as receipt for registration. You can ask for a print of that, it's accepted by Samui Immigration, we house owners that self-register online, also use a print.
You should be able to register TM30 yourself in person at Samui Immigration, we all had to do that once, bach when they began to ask for TM30-receipt when applying for annual extension of stay, thereafter we could continue online...????