Wireless Joint

We live in a rural area and (obviously) internet choices are limited. Up until yesterday, we had been using a hot spot router that I purchased off amazon, and the guy who sold us and set up our plans for ATT (came to the house) was able to get it set up as an unlimited phone plan. Unfortunately, the router died yesterday, and I don't know if we will be able to get the same sweet deal. Forgive me if I ask stupid questions. My knowledge base is somewhat narrow as I am generally just a consumer and am trying to learn and teach myself more about how these things work.
Is there a way to get ATT to switch it over to a new router? The line and plan are obviously still in place. Are there other options?
I have considered trying to get a hold of the "guy", but my guess is since he's really just sales, his interest in helping with this situation won't be a priority.

Can I ask what model did you have and what exactly happened to it or what do you mean by "died" ?

So you're using a phone plan in a modem? You can easily get a device to replicate that one. The folks at the WH can get you set up. Then you just have to change the imei and the apn to match that needed for your phone plan. If your plan is ATT no need to worry about ttl settings.

AT&T does and can see time-to-live all carriers do/can, they just don't have it written into the switch to deny service when data jumps like Verizon and its mvno's do, instead, they simply flag the account and wait for a rep to take a look, then they can and will either suspend or terminate your account, this is why everyone's ipad plans all went down. so yes if you are smart you will set your TTL for AT&T to 64 for the longevity of your plan/account.