With p3, don't bother to get the original cable. It will be expensive and since p3 was an entry level product, the cable comes with it was nothing special. U can order it from Ali Express which will be cheapest option. Consider this as an opportunity get a a better cable than the stock. May be there will be silver coated copper which may get u a slightly better highs and faster snappy sound on ali.
With c5 if out of warranty unless someone is willing to do a DIY work, u are out of luck. Most earphones without detachable cables are irreparable according to manufacturers book. They wont accept it for repairs as it's NOT possible to open the shells of earphones as they are glued or a single mould. During warranty they mostly give u another pair which is easy for them.
I don't think there is an official B W service center in south India.