Billing Migration & Technical Specialist

Onecom is the UK's leading business technology provider, shaping the way we work, connect, communicate and operate.

You will join a multi-award-winning company, with over 800 talented people committed to delivering great customer experiences driven by the Onecom Way;
Think Kaizen, Be Respectful, Build Relationships, Make it Happen, Work Smart, Be Amazing.

We're looking for an experienced Billing Migration & Technical Specialist to play a key role in a major billing platform transformation. Working as the billing Subject Matter Expert (SME), you'll lead the migration of billing processes and logic from our incumbent platform, Tekton, to aBILLity, ensuring accuracy, governance, and a seamless customer experience throughout the transition.

This is a highly visible role, working across Finance, Technology, Operations and Product teams to ensure billing integrity, protect revenue, and support successful delivery of a business-critical programme.

• Analyse and document existing billing processes, rating structures, discounts, credits and invoicing logic within Tekton.

• Translate legacy billing logic into future-state requirements and configurations within aBILLity.

• Support data mapping, cleansing, transformation and migration readiness activities.

• Lead billing validation, reconciliation, parallel-run testing and user acceptance testing.

• Identify migration risks, billing gaps and process improvements, driving issues through to resolution.

• Collaborate with technical teams, business analysts, operational stakeholders and third-party suppliers.

• Produce comprehensive documentation covering migration rules, testing outcomes, controls and operational handovers.

• Support cutover planning, go-live activities and post-implementation hypercare.

• Proven experience supporting billing system migrations, transformation programmes or platform replacements.

• Hands-on experience with aBILLity billing systems.

• Excellent understanding of billing logic, tariffs, recurring and usage charges, discounts, bundles and invoice cycles.

• Strong experience working with Finance teams on billing assurance, reconciliations and revenue-impacting decisions.

• Ability to analyse complex data and trace billing outcomes back to source systems and business rules.

• Excellent stakeholder management, communication and documentation skills.

• Strong experience in telecoms billing environments, ideally covering mobile, fixed-line, connectivity, managed services or subscription-based services

Holidays
: 25 days + bank holidays and buy/sell options

Other Leave
:
Birthday day off, 12 paid hours for flexible use, Volunteer day

Lifestyle
: 9% combined pension contribution and 4x salary life assurance

Rewards
:
Quarterly and annual employee awards, discounts on tech

Development
:
In-House Training Academy

Wellbeing
: 24/7 access to mental health support, discounted gym membership, free breakfast & fresh fruit, eye-care vouchers, financial wellbeing support

We believe that diverse teams bring a range of experiences and better ideas that fuel innovation. That’s why we’re committed to creating an environment where everyone feels valued, respected, and able to bring their authentic selves to work. We welcome applications from people of all backgrounds, experiences, identities, and perspectives.