Losing promo credits when upgrading plan

I just got the iPhone 13 pro and a watch. With this I also have a computer and am in college and would like to use more hot spot. I burn through what I have and would like to upgrade my plan to the get more data plan, but when I go to push through to upgrade the plan it says I will lose my promo credits on my watch that I get every month. (I used a 180 off a Apple Watch with recent iPhone purchase) that being said I do not want to lose those promo credits. But would love to upgrade my account (and pay more per month) for the extra hotspot data and free Apple Music. 

Re: Losing promo credits when upgrading plan
Customer Service Rep

Let's get this figured out. Please check your private message.