Delay in possession by more than double the committed time

Location/place: Mohali

Name of company/service: CGEWHO

I applied to CGEWHO (Central Government Employees Welfare Housing Organization) Mohali Ph-1 flats thinking it would be a safe bet and paid first installment in first quarter of 2007. As per brochure construction was supposed to complete in approximately 30 months but it is almost more than 60 months (5 years) and still no signs of possession, construction is under way at a snail’s pace.
They also increased the price of flats by 25% from the price mentioned in the brochure reason being increase in construction costs, but the delay is from there side and construction cost will keep on increasing with every passing year.
CGEWHO previously gave unsatisfied customers the option to withdraw from the scheme, but interst rate they offered was much lesser than the home loan rate I am paying.

As an end user what options do I have apart for waiting for possession.