1st of all, flat foot can not be ocuure suddenly as u said in 2013. U have to tell what kind of treatments or modification u hv done till now. Detail assessment of foot in weight bearing and non weight bearing position is required. Yes proper corrective and strengthening exercises can definately help you along with shoe correction..
Next Steps
consult hand foot specialist/ physiotherapist
Health Tips
So many varieties of foot arc is available in market and online which you can wear inside shoe, can attach to home Chappal, even u can wear with out any footwear by straps to keep you foot in proper arched shape.. find the most convenient for you