What type of switch is it ? If its a simple not manageable switch, it can't be possible to refuse a new connecting mac. It should update its cache than.
Try to connect another pc (lookup its mac for later reference) on the defectuous port and than arp on the good box. That should give you a good look if the interface even is alive, and if a mac adress is coming through.

If its a cisco switch, most of them are manageable and can be configured. I also believe those are able to refuse or not refuse macs. Also there you should be able to clear mactable manually

Greetz,