Mind you, the costs were not cheap - I'll just say it was around RM150k to RM200k, just for interior design — and this company is supposedly reputable, registered with both MIID (Malaysian Institute of Interior Designers) and CIDB. Sadly, those affiliations seem to mean little in terms of quality or accountability.

Before I hire a new team to take over, does anyone know where or how I can lodge a formal complaint?

At this point, I can't just let these people off for delivering such poor standard of work. I guess it's more a matter of principle.