Sucks, but do you have a picture to assess the damage? Don't you have repair kit that came with the board? If not You can order the proper material online (or local shop including rafting companies) and DIY. It is not too difficult but follow the steps meticulously..

Hot Sail Maui Superfreak Sails (Ultra Light) 6.7m & 5.8m

6.7m: Mast 430cm, Boom 194-196cm, Extension 28-30cm (Mint condition)
$200.00

5.8m: Mast 430cm, Boom 183cm, ext 10cm
Professionally repaired, as per picture..
$140.00

Hot Rod skinny Mast 430cm 100% carbon (sold with the sails only) $175.00 ...

Paroskite Resort, Paros has rental gear.. Their location has a strong venturi effect even if the Melten is quit often strong enough
Just a step away (next island) Mikri Vigla Beach, Naxos has rental gear..