When making on-line purchases with a credit card there seems to be a correlation between denials because of 'suspected fraudulent activity' and what is purchased and/or from what vendor. The purchase amount seems irrelevant. Woke vendors, everything goes right through. Vegetable seeds or a text book about electricity and magnetism... 45 minutes arguing with the card issuer to undo the suspension for a $50 charge.

Over the target.

Time for a new card company. A smaller card company.