Certain travel agencies around the world have chosen to specialise in 'Destination' or 'Overseas' weddings and will usually work with a reputable & professional wedding organiser in each destination.  You may find such an agency in your area.

Check with your travel agent as to whether such specialised services are available.

These days there are also many 'destination wedding' companies overseas who are in fact specialists in the industry but who do not have a presence here in Bali. 

Some of these companies recommend that you book everything with them and they will then fly to Bali to be here for your wedding when it comes along.  Remember these particular organizers have no 'self presence' on the island ie: no office, not permanent staff etc.  this means they are relying on some local assistance via the internet themelves. 

The price they charge for your wedding will then cover their airfares, accommodation and costs so that they can be in Bali for your wedding.  If not, then you will be relying upon their long distance, local staff to take care of your wedding in Bali.  Hmmmmm what is the advantage of doing this rather than booking with a reputable wedding organizer already in Bali and specializing only in weddings in Bali??

Why would you want to pay for someone else's trip to Bali when you have the option of excellent, highly experienced, wedding organizers, legally setup and operating full-time on the ground in Bali.  The best of these even have western wedding consultants to take care of you.  They are always here, working constantly with the various personnel and vendors involved in the industry. 

If you choose to book with a destination wedding company based overseas, do make sure they have a real organizer on the island handling everything for you on their behalf.  If not, then there would be no advantage at all for you to book with such an operation.