Spending $300 on an era toon should have netted a relic’d toon

You clearly don’t understand what you were spending on. You bought materials that were fully achievable free-to-play.  The benefit of this was higher placement in the Coliseum Leaderboard to get more Relic 10 or LST rewards. Yes, CG didn’t explain a lot but it wasn’t hard to figure out after 3 months.

For future reference, do not buy any of the materials for the purposes of getting gear levels if you do not plan on also spending on the Mk 7 or Mk 8.  If you only plan on level 70 or below, there is no spending required.  Only spend for the Leaderboard advantage.

Even level 75 is achievable on all 7 characters without spending anything on the Era materials so long as you got all the characters to 5-stars (with the 6th marquee character getting 5-stars on day 1).