Paramount plus on us promotion code

I have the same issue. I don't have a subscription or a need to cancel and wait for the current billing cycle to end because I'm not a paramount plus subscriber (yet!). I can't even get that far because it's saying the t-mobile code (different code) is an invalid coupon code. I think this is because paramount offers one week free trial to every customer and this is overriding the coupon code for t-mobile customers to sign up for their 12 months free subscription. This sucks because it's the same thing that happened with Netflix and I paid for the service myself for 4 years. I'm not doing that this time, then it's not a benefit really..