No heirloom shards?

This is how it works. Before heirloom shards were in the game every player is guaranteed a heirloom in 500 apex packs. Which means it could be your first or it could be your 500th (so any from 1-500). If you had opened exactly 499 apex packs, once you open the 500th one you WILL get a heirloom. Now that shards have been added, instead of getting a random heirloom, you get an apex pack that contains heirloom shards, which then you can buy the heirloom you want. The progress from the apex packs is still the same for shards, and thats what carried over. Its guaranteed heirloom shards between 1-500. All the packs you opened that were going towards a random heirloom is now going towards the shards. You DON'T get shards everytime you open an apex pack. 

My official lvl is 750 and I never got any heirloom. ( Play Apex since march 2019 )

Tenta abrir um pedido no suporte da APEX, se a garantia deles é herança entre 1º e 500º caixas, você deveria buscar seus direitos. 

It’s official I’m level 500 and no shards or heirloom packs so what do I do now I’m not spending another penny on this game till someone figures this out it’s incredibly annoying 

Account-level hasn't anything to do with getting an heirloom drop.
You need to open 500 Apex Packs or get lucky and hit the >-1% drop chance.

You get 1 pack per 2 levels and max level is 500, if you do the math then you've probably opened around 250 packs by the time you reach level 500.