You can request a call log from the website. In your account under privacy and security. However, it is limited to how many requests you can make in a year, I think it is 2. To get $15off12 promotion you have to port in from an eligible carrier. Therefore, you’d have to port out, then back in. The promotion ends on Jan 23rd.
Another option for reducing your monthly bill is by getting your friends and family discount code for $20 off a month out there for people to use, the person that uses the code and activates the SIM, you can earn a credit and you can earn up to 12. It doesn't have to be friends or family, I have posted here in the Savings spot forum and accrued credits that way. Bad thing is now Visible has been putting out better deals so it is hard to accrue these credits now. Hard to compete with the 3 month deal they had and the current $15 off for 12 month deal. Hopefully when the latest deal expires it will be easier to earn credits again. Good luck!