The estimated average salary for a CSA - Customer Service Associate at Firstsource Solutions is £51,852 per year or £25 per hour, but some professionals have reported earning up to roughly £75,122 per year (90th percentile). The typical pay range is between £43,399 (25th percentile) and £63,199 (75th percentile) annually. This is based on 44 salaries submitted by Firstsource Solutions CSA - Customer Service Associate professionals on Glassdoor, as of Jun 2026.