We have been staying in Samui for an extended holiday, and Bangrak Laundry is our local, they have been amazing.
Communicating with them is accessible via Facebook messenger or Line, and they are very fast to respond and excellent English.
The pickup and drop off your laundry where you are located, it's only 60 baht a kilo, and they have express service for extra if urgently required.
All your clothes are returned laundered, clean, folded and fresh scented. Recommend them for their customer service and value, and your clothes are always clean and fresh too.