Got a motorola razr v3 on ebay. Not reading SIM card.

EBay is notorious for selling "unlocked" cell phones that actually aren't. I have run into this problem twice. Unfortunately, I had to pay for an unlocking service to TRULY unlock the phone. Sellers figure you are not going to switch service and will never figure it out. If you shop for Unlocked AT&T Motorola phones, they figure that you'll stick with AT&T and never know that the phone is not unlocked. I switched from AT&T to T-Mobile and found out that my V3 Razr, and my Nokia 3590, and Nokia 3595 were still locked to AT&T. The Nokia phones I was able to unlock myself with online resources. Motorola attempts were unsuccessful. I found an unlocking service on eBay, worked like a charm. It cost me about $3. A Google search for unlocking services revealed very, very expensive unlocking services which did NOT work. Luckily I paid with Paypal and was able to get my money back through the dispute process. Services outside of eBay were $20 and up. And mostly ripoffs.

For a V3 Razr, search eBay for "unlock code Motorola Master Code or Manufacturers Code" don't waste time with carrier codes... go for the heart of the problem. Get a Master Code for your model Motorola, and you'll never have to unlock it again, regardless of carrier.

It may be caused that when you take out sim from old phome it has damaged, try for old one is it still working? if not then your sim is dead, also old phones made SIM-s to be bend and such SIM-s have difficlt electrical connection with new phones.
Also find if "this sim only" is activated in your phone.
It must give you signal, Insert sim card, or insert proper sim. If insert sim card warning card is damaged or have not enough good connection, if another, then this sim only is activated you first you must unlock it to work .