I am traveling back to the US. Can I use my (old) US SIM card. It is the same phone Samsung S-9 I had in the US. I switched to a Dutch T Mobile provider from a US T Mobile provider when I moved to the NL.
Is that US account still active?
No. I closed it.
Then it would be like inserting a Verizon SIM - it wouldn't work if the acct isn't active. It will work on WIFI, if that switch is on, but you'd have to activate an account to get any US Sim to work.
Yeah, you might as well start over with a new prepaid service (if a temporary visit). Unless you've been paying your US T-Mobile bill all this time, the old T-Mobile SIM is junk.