I'm a bit confused because the GoldTrail website makes no reference to the Club Alize. It doesn't feature in their range of accommodation. Perhaps the confusion arose at the booking stage?
To complain, send a letter by recorded delivery, addressed to Goldtrail Holidays, Unit 41-45, KingsPark Business Centre, 152-178 Kingston Road, New Malden, Surrey KT3 3ST.
Your letter should give details of your complaint and make it clear that you're making a demand for a refund of �150. (Obviously, you should keep a copy of your letter).
If you don't get immediate satisfaction, write again, stating why you regard the firm's response to be unsatisfactory. (This second letter is important because you can't involve ABTA until after you've made two attempts to resolve your problems).
If that fails, contact ABTA and/or the media. For further information about these options, see my responses, here:
http://www.theanswerbank.co.uk/Travel/Question 258896.html
Chris