Evri complaint: Courier

I received an email to say that my EVRI parcel had been delivered with a photo attached to the email, they had stated that they had placed the item in my porch at 16.14, the photo was not my porch or my address and someone was in the house at that time, and nothing was delivered. I then got in contact with EVRI who kindly responded to my email straight away, I followed their instructions and contacted the courier for Guernsey, I was given a telephone number which i text only to receive a reply 2 days later and then basically accusing me of lying and why it had taken 4 days for me to contact them, 3 days on and i am still waiting for a solution, i have also contacted the sender.
My complaint is only for the Courier of EVRI in Guernsey, all other agencies have been very professional
Please can someone deal with this and at least speak to the courier as this service is terrible and i still haven’t received my parcel.
Thank you