BYOD $500 rebate chargeback

I opened 5 phone lines on March 6, 9, 10, 11, 12, 2022. I received 5 gift cards of a $500 rebate. I canceled the entire account on April 8, 2023. And customer service told me I must pay back the $2500 rebate because I canceled early. The last line was activated on March 12, 2022, since that day to March 12, 2023, is 12 months.
I canceled on April 8, 2023, but they charged back $2500 rebate.
I only changed phone numbers, I haven't upgraded devices or phone plans since the activation.
I have explained this to them, but they are trying to ignore the issue.
Please tell me what I should need to do now.

1 Reply
Customer Service Rep
We are always a PM away. If it is beneficial to continue, we will be on standby.