Phone promotions for new watches only

I'm so frustrated with T-Mobile!  I have been with this company since 2004 and continue to be punished for being a loyal customer.  I have a series 4 watch purchased in 2019 with a line and have been looking for any offer on watches for the last 2 years and the only deals they give are for new lines.  It's upsetting because my cellular doesn't even work on my watch anymore like it should and so I'm willing to get a new watch but would like to purchase on a promo.  So to do so I  have to be inconvenienced for 90-days and then add the line back on.  I find this upsetting.  I've been patient and I just don't feel like TMobile cares about existing customers.  It makes me really sad