Personally, I wouldnt trust it. Their commitment in writing is binding. So if you send them the money and they dont hold up their end of the deal, how will you prove to the CRAs that this is what they said? You can try sending your payment "restricted endorsement" but thats not as binding either. I have done it and it has worked, the COs never showed up on my CR but I didnt have my CR in hand to know whether they were on in the first place. Just know they never got on their.