I have 1300+ CPS coin
would you please let me know how can I convert them in BTC or LTC?
I haven't used them and I don't have CPS coin but have you tried to go directly to coinspayment.net and trade there? IIRC, you can use their p2p exchange to convert/buy with BTC, LTC and other coins.
Another way is to look for someone who's interested to buy it here in the forum just like what OP did but I don't know if he found a buyer.