Hi aarvee,
Dormio is one of the members of this site which means that I think highly of them and that I believe that they compete well with the best in the industry in terms of their quality, value, service, transparency, and knowledge.
They send a hard copy of the warranty with their mattresses but as John mentioned … their warranty is listed on their website here and all you would need to do is print it out if for some reason it’s not with the mattress (or if you need an extra copy) and this certainly wouldn’t be a concern to me,
I would also keep in mind that the warranty of a mattress has very little to do with the useful life of a mattress and how long it may be before you need to replace it. Warranties only cover defects in a mattress and not the gradual (or often rapid in the case of lower quality materials) loss of comfort and support that is the main reason people will need to replace their mattress. There is more about mattress warranties in post #174 here.
I talked with John this morning and my understanding is that the specific mattresses you purchased are listed on the invoice and they listed it the way they did because you received a package deal with a discount so there wasn’t a specific individual price for each mattress and it was just listed in a way that the invoice added up to the total for the package deal you received. I’m not sure why this would be a concern either but if you aren’t happy with the way the invoice is listed I would call them and I imagine they could itemize it differently.
There is also some good information about the most important parts of the “value” of a mattress purchase in post #13 here which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability (how well you will sleep), durability (how long you will sleep well), and the overall value of a mattress compared to your other finalists (based on all the parts of your personal value equation that are most important to you).
It sounds to me like you made a good quality/value purchase for a package deal with a discount and I personally wouldn’t have any concerns with either of the issues you mentioned but if you do have any concerns for any reason then of course I would talk to John at Dormio about them.
Phoenix