I believe they are asking you how did you get those tokens. If you got them from the ICO, how much did you invested, etc...
yeah I participated through BANCA ico pool with 3 ether and got 1.1 million BANCA tokens. I already told them this though along with etherscan links of transactions when I sent 3 ether and when I received 1.1 million tokens.
Maybe its still lacking which you would really need to add up some screenshots regarding on such transaction like conversation or any verification that you had purchased tokens either on your email or on the website itself of that particular project.It seems they do become more strict because I had remembered last transaction with having a 10 ETH transaction doesn't have this kind of verification or hassle from them yet it goes without any problems.