After Sales - worst experience

This has to be by far the worst after sales experience, I have ever experienced.

I have been requesting a paid up letter since Nov 2018 and to date have not received anything. Every time I request this i'm told about an SLA surely the normal SLA should be over ridden as this is now an escalation which has still not been attended to.

The consultants whom I have been speaking to from the customer service call center have no sense of urgency and instead tell me this is the process that needs to be followed.