Importing contacts from old dumb phone

My mom uses an ancient Samsung SGH-C140 dumb phone with a mini SIM that has 150 contacts capacity. However all her contacts are stored on the phone, and there are around 400 of them. After all these years I have *finally* managed to convince her to allow me to buy a new phone for her (that too only when the keypad of the old one has given way)! Now the problem is that the new Android phone uses a micro SIM, and I'm at a complete loss as to how to go about transferring those 400-odd contacts to it. The only option I could think of was to go get the mini SIM cut to micro SIM size, then repeatedly use the **Copy All Contacts to SIM** feature to transfer from the old phone to SIM (while using the outer mini SIM sized bracket), and then from the SIM (without the bracket) to the new phone. The problem with this method is that the Samsung phone doesn't allow me to select the contacts, and always copies the same set of 150 contacts to the SIM before complaining about lack of space. (Aargh, which idiot made this phone's software?!) Since I simply can't afford the loss of any of the contacts, what do I do? Do I *really* have no other option than to sit and manually read and enter all those contacts again? P.S. I thought briefly about checking on some sort of PC software for the ancient phone, but even if it exists and can run on Windows 7/8.1/10, I have no clue where I'd get the required phone-to-PC cable from at a reasonable price. Edit: OK, so the UK site for the phone mentions **Samsung PC Studio Image Editor** and **Samsung PC Studio Internet Access**. I assume the latter is the one that *might* support contacts export, but aside from the cable issue, there's the additional problem of how I would even export those contacts using the software to a format that Android would understand. If the software supports export/import of contacts using some proprietary format only from/to the phone itself, then there's obviously no point using it.