This is an appeal from an order of the Commission affirming a referee’s decision to dismiss appellant’s appeal as untimely. The appeal was taken by appellant as a claimant for unemployment compensation.

Section 443.151(4)(b)l, Florida Statutes (1982) provides:

The claimant or any other party entitled to notice of a determination as herein provided may file an appeal from such determination with an appeals referee within 20 days after the date of mailing of the notice to his last known address or, if such notice is not mailed, within twenty days after the date of delivery of such notice.

Rule 38E-5.05, Florida Administrative Code provides:

Appeals filed by mail shall be considered to have been filed when deposited in a receptacle of the United States Postal Service. The postmark shall be considered evidence of the date of posting.

The record is not clear regarding certain factual matters which are important to this case. In order for the appeal to have been properly dismissed it must appear that the notice mentioned in the statute was mailed more than twenty days before the appeal was filed in accordance with the administrative rule. In order to make such a factual determination it is necessary for the Commission, or its proper designate, to hold a hearing and consider all relevant evidence on this issue, after due notice is given to the claimant. Due notice was not given to appellant that there was a jurisdictional question to be heard and decided. Therefore, we quash the decision affirming the order dismissing the appeal and remand this matter for the hearing and such further proceedings as are warranted.

REVERSED and REMANDED.