Can I cash in my provident fund while employed?

Your fund membership is governed by the fund rules. If the fund rules specify that employees on short-pay are not eligible for employer contribution, then the employer has to comply with that. Check with your HR department, to confirm if this rule is in place or not. It is not clear from your question whether you are still contributing, but it probably does not matter: the Income tax Act stipulates that you can only withdraw from your provident fund in the event that you resign, or are dismissed or retrenched. This does not appear to be the case, so you will be unable to withdraw from the fund.