Several reasons could explain why a hiysystem.com promo code didn't work:
- Expired Code: The promo code might have expired.
- Usage Limit: The code may have reached its usage limit.
- Minimum Purchase Requirement: Some codes require a minimum purchase amount.
- Product Exclusions: Certain products might be excluded from the discount.
- Incorrect Entry: The code might have been entered incorrectly.
- One-Time Use: Some codes are valid for one-time use only.
- Region Restrictions: The code might be restricted to specific regions.
Checking these factors can help determine why the promo code didn't work.