What qualifies as a BTS device?

I purchased a MiFi® X PRO hotspot in December 2022. At that time, the T-Mobile customer service rep told me I qualified for the promotion "UMTS Network Retirement - $200 off any BTS device" and that I'd get a $200 credit to my account. I've never received the credit, even after chatting with customer service at least 3 times since then.

Today, a customer care representative told me that I didn't qualify for that promotion because the hotspot is not a "BTS device". Does anyone know whether a hotspot qualifies as a BTS device? I feel deceived!