Technician will not contact me, on second day of waiting for motherboard to be replaced

Service request put in July 21. Was told first available date was Monday July 25. Did not hear from technician. I was given tracking number for parts and that shows that the part is waiting to be picked up. I’ve chatted with several people on support and was told they would try to get technician to call me within an hour.  Still nothing. My main contact who started the service request hasn’t answered any emails in two days and it’s impossible to get same person twice in support!    I really need my computer fixed In order to get work done for a deadline. Can a different technician be assigned if first one never shows?