Organise the trip yourself

Twin group provides no service that you could not do yourself for a much cheaper price.
By all means go to Montpellier and take the course, but cut out the middle man. They charge more than the school for classes and a homestay arrangement and will not hesitate to tell you that it's your fault when they've provided you with misleading information. They will calmly place you in a homestay 2 hours away from Montpellier and repeatedly tell you that it's less than 1 hour away. They have little desire to know whether you're satisfied with the program and will make no effort to follow up with you after you've paid your money.