I am writing to express my concern regarding an unauthorized rate increase on two of my mobile lines. Despite reviewing my records, I have received no prior notification of these changes, aside from standard electronic billing statements.
Furthermore, while I currently maintain four lines and was recently offered a promotional rate of $30 per month for additional lines, the monthly charges for my existing service have increased instead. I would appreciate a detailed explanation for these adjustments and a correction of my billing to reflect the agreed-upon terms.