Short answer. Almost certainly not on that ground. The Labor Code's neglect cause requires neglect that is both gross and habitual, and one absence is neither. A single lapse can support a lesser penalty, and in rare cases another ground entirely, but it does not fit this one.
What the law says
Gross and habitual neglect by the employee of his duties
Labor Code, Article 282 — Just Causes For Dismissal. Read the full provision →
Two words, two separate requirements
The ground is gross and habitual neglect, and the conjunction matters. Gross speaks to degree: want of even slight care, not an ordinary mistake or a bad day. Habitual speaks to repetition: a pattern of the same failing over time. An employer relying on this cause has to show both. A single absence, however inconvenient, cannot be habitual by definition, so the ground fails on the second requirement no matter how much damage the absence caused.
Employers often reach for the wrong ground
Where a single incident is genuinely serious, an employer will sometimes try to reclassify it — as wilful disobedience of a lawful order, as a breach of trust where the role is one of confidence, or as serious misconduct. Each of those has its own elements and its own proof problems, and none of them is satisfied simply by relabelling an absence. Watch which cause the notice to explain actually charges you with, because the employer is generally held to it, and a cause that does not fit the facts is the whole defence.
Absence with a reason is not neglect at all
Before any of that, ask whether there was neglect in the first place. An absence covered by approved leave, sick leave, a genuine emergency, or a notification the employer received and did not act on is not a dereliction of duty — it is an authorised or excused non-attendance. Neglect describes a failure to do what you were required to do; if you told them, or if the circumstances made attendance impossible, the factual predicate for the ground is missing before the gross-and-habitual test is reached.
What to preserve
Gather anything that shows you gave notice and why you were out: the message or call log, the medical certificate, the approved leave form, the reply from your supervisor. Then look at your own attendance record, because the employer will need prior, documented instances to argue habituality — and if there are none, or if past absences were excused at the time, that record is working for you. Keep the notice to explain and your written reply, and take advice before the hearing.