Contactor is 220V AC. Snubber is 100R in series with 0.47u. across contactor coil.

Do you have snubbers across the contactor outputs.

previously i was using ds1232. that has not solved my problems. now iam not using anu supervisor at all.

Use a supervisor it certainly helps. May be you can't see any immediate effect but in due course it will certainly help.

my problems started when i switched to 3.3 micro. previously i was using RD2.

As Micheal has already said these 3.3V micros are more sensitive to noise than 5V ones. You can do one thing keep the crystal frequency minimum that would do the work.

If I am right your circuit is not on a bread board or a vero board but it is a well laid PCB with solid ground plane and is neither auto routed but manually routed with care isn't it?

Thanks & Regards,
Prahlad Purohit