Specifically, which companies have you dealt with and can you recommend them as a reliable website development partner?
I will recommend you to read some business review sites, like Foursquare, Clutch, Trustpilot, etc. I also recommend finding websites you admire in the wild, asking for an introduction to their head of digital marketing, and asking them who they hired. Moreover, all established web development companies have previous clients. It is a good practice to contact a team’s clients and ask about their experience. You can learn more about the quality standards of the e-commerce team by checking their overall digital presence. So just analyze their website, content, etc.
Or you can check these guys with all the mentioned below methods, https://elogic.co/about-us/
visit www.rnssol.com or google RNS Solutions.