Here is their phone number. It's a mobile phone. Phone them when you arrive in Martinique.
You'll find taxis in Pointe du Bout next to the Kalenda hotel. I don't know how much they'll ask to go to Ti'plage but it's not very far.
Enjoy!! good food, good feeling.
1, allée des raisiniers
Tél : 06 96 29 59 89