Yeah, I would recommend everyone take precautions when buying PayPal my cash codes. Most of these codes are known to be bought illegally, however most of the time they will not result in chargebacks. However if you redeem too many codes PayPal will label your account as high risk and shut you down. I have used a few of these discounted codes on other websites and haven't had any issues besides account limitations.
That is good to know where were you getting them, I only tried it once and my account was flagged.
Crypto Market, the seller is no longer active so you will have to find another seller, also remember to always use Escrow.
My opinion you should only buy the codes that have receipt proof.