Struggling with Discovery Invest

Struggling to get 3 tax certificates from Discovery. Can't get it from the broker, he told us to phone Discovery Invest customer service. If you phone Discovery Invest customer service they can't assist without the brokers number. We have mailed Discovery complaints, no success. We don't have an internet profile to logon, because it is still on the deceased name. At the end of the day SARS still need the tax certificates. So how do you get a tax certificate if the bucket keeps on passing?