The project aims at analysis of Customer Complaints/Inquiries received by a US based mortgage (loan) servicing company.. The goal of the project is building a predictive model using the identified significant contributors and coming up with recommendations for changes which will lead to 1. Reducing Re-work 2. Reducing Operational Cost 3. Improve Customer Satisfaction 4. Improve company preparedness to respond to customer. Three models were built - Logistic Regression, Random Forest and Gradient Boosting. It was seen that the accuracy, auc (Area under the curve), sensitivity and specificity improved drastically as the model complexity increased from simple to complex. Logistic regression was not generalizing well to a non-linear data. So the model was suffering from both bias and variance. Random Forest is an ensemble technique in itself and helps with reducing variance to a great extent. Gradient Boosting, with its sequential learning ability, helps reduce the bias. The results from both random forest and gradient boosting did not differ by much. This is confirming the bias-variance trade-off concept which states that complex models will do well on non-linear data as the inflexible simple models will have high bias and can have high variance. Additionally, a lift chart was built which gives a Cumulative lift of 133% in the first four deciles