I NEED HELP... PLEASE?

I buy my iphone in ebay because i cant afford the brand new iphone. but when i get the iphone it is activation lock. the seller forgot his icloud password and I cant contact him anymore. he just erase his account on ebay and i cant call him. IMEI : 359232060345564 iphone 6

please respect my concern? it is really a bad experience.. . i hope you can help me i'm looking forward to it.