Their block / spam reporting tool is useless too.
Quite often I will watch trending topic spammers and instantly hit the report for spam button.
Three days later those same accounts are still spamming :(
Here's another tip for Twitter:
Take the advice of authoritive accounts that report spammers. Define an authoritive account as one that is either
a) Blue ticked
b) Has been online for X months / years and the ratio between followers and following is 10:1
If more than 10 authoritive accounts block a spammer then ban that spammer account instantly. It's not good letting that account run for 3+ days as too many accounts would have been infected by then.