You had deal with him before this time? Screenshot had some conversation before. However, telegram chat can't be a proof as it can be faked too. Can you provide proof that receiving address of the transaction is owned by the seller? Where did he give you the address? Telegram or on forum or posted anywhere else?

A little advise, never have a conversation outside the forum when you are having a trade here. Forum chat can't be deleted for both side by one.