This is on you. The descriptions are pretty clear on what content you will receive access to. Sounds like the issue is a failure to read and/or understand those descriptions.
The descriptions do tell you what content you WILL have access to.
It's your fault for not realizing those weapons are seasonal weapons and require you to purchase season passes to access them. Once again, your fault for not doing the research before buying a product.
I think the issue is you [b]assumed[/b] you will receive those weapons without looking into weather or not you actually would.