Evri complaint: Parcel not delivered and Customer Support not responding

I sent a returned item parcel with paid tracking using Evri on 13th February. Evri tracking shows it was delivered to their depot on 14th February. The last message on their tracking app is
07:43 – Fri Feb 14
Your parcel is at the delivery depot and we’ll let you know when it’s out for delivery
I called the Evri customer service number on 20th February for an update and got an automated response and received the following email on 21st Feb:
Update
250220-021818
Good morning Anthony,
I’m Claire and I’ll be taking care of your delivery enquiry.
Firstly I’m sorry we haven’t delivered on time for you. I can see the reason for the delay is that the parcel missed the connection to the courier.
We are aiming to get your parcel back on track and delivered today.
I’ll check first thing tomorrow that your parcel has been delivered. If it hasn’t, I’ll be in touch before 10am.
You don’t need to do anything. I’ll look after things from here. If you have any questions you can reply to this email I’ll be happy to help.
Kind Regards,
Claire
Evri Customer Services

This was the last communication I have received from Evri. That was 11 days ago. I have since email them twice and called their customer support several times but no response whatsoever, other than they have received my complaint and their customer support are dealing with it. Still no responses.
My next steps will be to email their leadership team directly, including the CEO ([email protected]) to request them to have their customer support team to respond to me detailing their next steps to resolve the issue.