The company claimed that it never shared "personal data" with partners or other outsiders, and that it had solved the problem from September 17. There is also "taking steps" to make sure this doesn't happen again. However, Twitter did not know how many may have been affected, and reported that this was primarily "transparent" about what happened.
This probably won't go well with critics as Facebook caught flak just over a year earlier to use phone numbers for ad targeting. Whether Twitter intended to use phone numbers or not, the effect is the same ̵