There are a few points need to be clear before any next course of action.

1. SPA or Sales and Purchase Agreement between Purchaser and Developer in this case should be a standard agreement following KPKT HDA article. It does not mention anything about the landscape/perimeter fencing in relation to your parcel/unit. The major Black and White document to be referred. Housing Tribunal which was established under the purview of HDA shall only facilitate complaints in relation to clauses established/described in the SPA. Hence, personal opinion this SPA only cant provide any specific ground for your claim.

2. Secondly, any "official" marketing materials even with/without disclaimer, showing any view/shoots/description of the "fencing" is the main issue now. To go further, only official marketing material shall be utilized as the proof for your claims, anyhow there are precedent case that marketing materials by developer shall be in binding but its done at court level in which time and monetary cost would be a major concern.

3. Developer branding. That is the hardest part to quantify and should be your current best resort to level up your complaints.

Above all are just personal opinion.