switching sim cards or carriers

[david_1979.]

Hello, I recently purchased a new straight talk byop plan. I have a metro pcs samsung galaxy avant that I network unlocked with the carrier code. I used the term Mobile sim card, because I thought I had to since metro pcs phones run off to mobile networks.I'm moving, and will have no coverage, unless I switch to AT&T.
I lost the AT&T sim that came with the byop package. So my question is, can I use a different AT&T sim card, or how else can I switch carriers from t mobile to AT&T?

[Lindsay_ST]

Hi david_1979. My name is Straight Talk Lindsay. We are sorry for the trouble. Let me help you. We need to take this issue offline, so I can address it further. I will contact you directly with a private message. Thank you.