Without the requested information, I can only provide you with the following general response, which will hopefully still answer your query. First of all, I am sorry to hear about the issues you have experienced in your situation.
The key issue is whether the bonus was guaranteed or discretionary. Workplace bonuses can, in their nature, overlap in the way they become payable, which can sometimes create some difficulties. For example, they could be contractual with discretionary eligibility, contractual with guaranteed eligibility or discretionary altogether. I will summarise the usual positions below:
1. Contractual bonus
This is the preferred situation as the bonus terms are clear and transparent as they are contained in the employee’s contract or associated bonus eligibility document. The employee’s participation in a bonus scheme is practically guaranteed, although it would not automatically mean they are also eligible for receiving payment under it. Whether that happens depends on the criteria set out in the associated terms.
Assuming the conditions have been met, an employer will rarely be able to refuse payment of the bonus as doing so would be acting in bad faith and considered unfair. It is also going to be a likely breach of the implied term of mutual trust and confidence, which exists in every employment relationship. They should pay that, even if it is to be backdated
2. Non-contractual/Discretionary bonus
These are actually the more common types of bonuses. There is no automatic right to a bonus, allowing the employer flexibility in choosing if and when a bonus is payable and such decisions may be made entirely at the employer's discretion and on their own terms. The key aim is to avoid placing the employer under any obligation to implement a bonus scheme or make any bonus payments. A scheme where the employer has total discretion on whether to pay a bonus or not could be difficult to challenge. However, less stringent schemes where the employer may only have partial discretion or still form an opinion on eligibility or base it on performance could potentially be challenged under the fairness arguments mentioned above.
It follows that even though a bonus clause may be described as being at the employer's discretion, there are circumstances, mainly in performance-based eligibility, where this discretion is removed and the bonus would automatically become payable if the eligibility criteria have been met. The employer must have reasonable grounds for not paying that bonus and be able to show that it has acted in good faith.