Hi Mia! Hope you have a great time in Vietnam. Unfortunately I do not have the contact details of the travel agency, though many of the different travel agencies offer these tours. Just be aware they may charge you extra as you are not in the country yet (this is often a theme when booking any tour outside of a country). Alternatively why not check out what tours run on Viator or Get Your Guide? That way you can check out reviews and know exactly what to expect :)