Many thanks for your patience, I am pleased to be able to continue assisting with your query now. First of all, I am sorry to hear about the issues you have experienced in your situation.
If someone has genuinely been overpaid by their employer, they will likely be responsible for repaying some, or all, of that money. The employer can rely on the common law remedy of restitution to recover the overpayment. That attempts to prevent the unjust enrichment of the employee at the expense of the employer.
From a legal perspective, an employer has the option to deduct any previous overpayments from the employee’s current wages. This is a right that they have under Section 14(1) of the Employment Rights Act 1996:
This basically means that they can withhold money from any future wages they pay the employee until the amount that is owed has been repaid.
However, this is not an unconditional right and the employer is still expected to act in a fair and reasonable manner; something they are required to do under the implied contractual term of mutual trust and confidence. What this means is that whilst they can make the deductions to start with, they need to be conscious that this will reduce the employee’s wages and they should proceed in a fair way. That would involve discussions with the employee over the proposed deductions and agreeing on an amount that the employee is reasonably able to pay, taking into consideration their outgoings.
If the employer was to proceed with the deductions without checking what effect they may have on the employee, and they end up missing direct debits, bills, etc, that could amount to a breach of trust and confidence by the employer and potentially allow the employee to consider challenging them, including seeking compensation for any charges or penalties incurred as a result.
If that happens, then in the first instance, this should be pursued through a formal internal grievance, before any further action is taken. If the deductions have not been made yet, it is important to discuss with the employer a way forward and what repayment amount/interval should be applied.