If you created the accounts for good reasons (like one for the blog, one for an APP...) you can contact them. If you created them; just to build following, so I think you used the same IP!
why don't you just stick with building one account. In the long run it will be 100x more valuable than all your spammer accounts. Besides, no one likes a spammer
For example you have 2 niche sites 1 selling kids toys and 1 selling sex toys? How can you market them in one account?
Firstly, why did you have to register so many accounts in a single day. Even if you had dire needs, you should have registered only 1 or 2 accounts a day. Obviously Twitter will ban such spam attitude. I think it blacklisted your IP. Did you try registering a new account?
I think twitter banned your account becoz you opened one too many from the same IP. Dont waste time trying to contact their help desk or something like that. They never respond and you wont get the accounts back. Simply open a couple of new accounts from different proxy IP and different email id.
I emailed them and they reinstated my accounts. I gave them a good reason though. I would say email them before you make new accounts
It is not true that twitter does not allow multiple accounts. I have more than 5 accounts and each is for a different niche. But I don't open many accounts on the same day. I open them on different days.