One attribute includes another attribute
The two features "voice mail calls" and "voice mail plan" are related but they are not linearly correlated. "Voice mail plan" still contains some information that is not available from other features. Why do you want to remove "Voice mail plan" in first place? If you need to decrease your number of features, you can try dimension reduction (linear or non-linear), this way you make sure most of the variance of your feature set is considered for building your model.