In any taxation year, contributions that exceed your annual RRSP deduction limit won’t be eligible for a tax deduction in that year.
As well, excess contributions may be subject to penalty tax until withdrawn from the plan if your cumulative excess contributions are above the limits set by the Income Tax Act.
Reach out to your Plan Administrator and make the necessary adjustments to your payroll contributions.
You can also reach out to CRA for additional guidance depending on the over-contribution amount.