No service- new SIM sent

[Sadporcupines]

Mods, if this is a repost, please feel free to clean it up. I tried to edit my last one and it disappeared.

Purchased a Samsung galaxy 8 from straight talk. I travel between 3 towns, all within about 80 miles of each other. I went to one town for the weekend and service was fine. However, when I travelled to the other today, I had no service. Contacted ST-Kevin on live chat and he said he needed to send me a new sim which will take 2 days- there is no option to purchase one locally, which is terrible as I can not take client calls and am losing business. After driving back home for about 30 minutes, service picked back up just fine (with the original sim card, as the new one is still shipping).

I called ST customer support when I got home because the loss of reception made me believe that the service area my phone stopped working in may be roaming. I don't want to get caught in a situation where my business travel leads to me getting booted off randomly if I use my phone too much in another area, which is in the TOS. Phone customer service was equally as difficult, as they couldn't understand my questions, much less answer them. So hopefully someone out there in the forums has had a similar experience and knows...

1)If I travel within an 80 mile range that has coverage by the same network (ie ATT), does that warrant roaming and thus subject my plan to termination by straight talk?

2) What is the purpose of a new SIM card? Does it change the service provider to another one that can provide a continuous service ?

3) If straight talk can not provide service to me or terminates service based on the fact that I travel to too many locations, do I have to wait a year to have my phone unlocked to take it to another carrier or am I mi dreading the terms of service?

With all due respect, I am not looking for an ST customer service rep recommending me to "take the conversation to private message" as the last two reps have been wholly unhelpful and don't appear to be interested in escalating the issue to the point I find any resolution. If like to be able to return this expensive phone sooner rather than later if it comes down to it. I can't afford to be strung along with promises that "we'll look into it."