your site earn 1000 btc a month from advertisements
False. Latest auction result
https://bitcointalk.org/index.php?topic=968397.60 not even close to 100 BTC a month.
just login my account and seen
you have two option to staff to control this?
first ban all signature advertisements accounts
or Allow us to rent our space for advertisement
You are allowed to rent your signature space for ads. That's why there are so many signature campaign out there. I've been renting my signature for over a year and never been banned.
You are banned because you were making insubstantial posts (spamming the forum) to earn BTC from signature campaign. That's all.