Yes, I would say no more than 4. (and honestly if you are disputing duplicates - count those as 1) You need to wait the full 30 days until the investigation is over before sending another round of disputes.
You
can dispute them by regular mail......but I suggest sending them certified mail (but not RR). This way you can track them and you know exactly when the 30 days begins.
Also be sure to either hand write or type with purple or teal italic font.
