RSA Retail Savings Bonds: SHOCKING Customer Service

I am totally disillusioned. This must surely be the worst customer service I've experienced in my 60 year life!!! I've been trying to update my personal details for almost a month now but to no avail. After logging numerous requests, and the last time on 15 May (with more substantiating documents than required), it has still not been done.

I've been begging for feedback from RSA Retail Bonds for many days now and get absolutely NO response. Out of desperation I've also sent emails to the Complaints Dept but even they do not respond at all. Where should one complain then?

I deeply regret investing my life savings with RSA Retail Savings Bonds, if investors are treated this badly when trying to make minor changes to their personal details, I can only imagine what will happen if you need to get funds paid out on request or at maturity thereof. I am worried...