ECU problems

[StuartGS430]

Hi 

Looking for some help. I recently purchased a 2005 GS430. Picked it up cheap as it has the "hard downshift" problem. After doing some research, found Youtube videos posted by Car Tune Company NZ and it turns out to be a bit of a common problem. So got in contact with them and posted my ECU to hm for repairs..... that was back in November last year! I did receive back an email late December from him apologizing for the delay. Since then I have sent follow up emails and tried calling with no response and I am really getting worried I will never see my ECU again.

My question is, has anyone had dealing with him in the past? 

What are my options as apparently the ECU from my vehicle is quite rare (part No. 89666 30320). I presume an aftermarket standalone ECU would be expensive?