regardng using a Samsung SIM in iPhone

I inserted my Samsung's SIM (Tracfone service provider) into my iPhone 8. My iPhone 8 works alright except for two functions I've noticed, so far:

1. My iPhone 8 does not notify me of any voicemails received. I must manually check my voicemail. This may be a Tracfone problem, have not yet contacted Tracfone to confirm.
2. While my iPhone 8 notifies me and shows me text messages, not all text messages are readable; some are made of letters and numbers in nonsensical order, instead.