Refusal to provide certificate of service

I use to be an employee of FNB, I resigned in November 2024, I have requested my previous HR representative to provide me with a certificate of service which is required for me to obtain work abroad, which is being refuaed, I have explained that I no longer bank with FNB or have access to their systems to get the document my self but still I am being refused, to what lengths does a person need to go to get what is required because these days asking doesnt mean anything wether you are an internal or external client no body cares, you always have to resort to laying complaints and going to extremes to get assistance. This HR representative always either passed the bucket, ignored you, or straight forward refused to give assistance, how far must a person go.