I'm sure it's a counterfeit. Sorry to hear that

There are stories of counterfeits popping out from Greech as these sellers appearently buy them from China which is the main source of problem. I wasn't expecting a rather common coin like that to be counterfeited. As for a reference, here is what a genuine coin from the same era should look like:

There is NEVER a rim that is as thick as yours - which is one of the tellsigns of casting. Also, the weight of a genuine coin from that era should be 20.73grams. If it is significantly lighter as I suspect it's cast in either nickel or iron, it's unfortunately a counterfeit.
I highly recommand you contact the seller to demand a refund immediately else if you did pay with paypal, you should be able to open a dispute as you purchased a counterfeit.
Good job in finding this forum to confirm your suspection.