Sometimes we need to use synthetic ingredients to help with the formulation, we never use nasty ingredients, only safe ingredients for skincare. 
Ingredients affecting 100% Natural Claims and what they do:

Sodium Ascorbyl Phosphate
- is a stable, water-soluble form of Vitamin C that functions as an antioxidant.

Phenoxyethanol is a widely used synthetic preservative that has global approval for use in all cosmetic products in concentrations up to 1%. We stick to below this level. 

is a synthetic skin-softening agent also used as a preservative, a carrier, or suspending agent for other preservatives such as phenoxyethanol.

PEG-100 Stearate is a very common surfactant and emulsifier that helps water and oil to mix together.