During my hiring process at job, I was promised a salary review after 3 months however when that 3 month period was up, I was denied my salary review because it coincided with a new company taking over the operation. A week before I requested the review, my co-worked received his 3 month salary review and got an increase in pay. When I complained to my boss he told me not to worry about it, my salary increase will be reflected on the employment offer from the new company. When my offer came in, the increase in pay was very small and I was not satisfied. Earlier today I found out that this co-worker(who started a week before me) received an increase in pay when his new offer came through as well. So now there is a huge pay discrepancy between myself and this other developer, we do this same job and have same qualifications. This wasn't done on purpose in my opinion, the previous boss was very lazy and I think this hiccup came from a lack of effort on his part.
I have a phone call with my new manager today to discuss this issue. How should I approach this?