if you need to send 250 DM a day you may be better off sourcing 10 or 20 twitter accounts and then spread the DM, so only 10-15 max per account. I do the same for cold email and pay for multiple inboxes. if you need a site to buy accounts this may be one, bulkaccountsbuy dot com
I have used it only once and I heard other people using it. maybe do not use your primary card there. Anyway just ideas, hope this help