Yes, it does effect business. Mobile compatibility is important nowadays. First, it affects SEO, then, mobile compatibility improve the user experience for mobile users and the most obvious reason is that we know that mobile visitors are generally very impatient, if a website does not appear to be working, they will leave it right away.
Yes, that is very important to have a website that is apdated to mobile usage. The biggest disadvantage of not having it is that Google will treat you as a lower competitor than other related websites. And yes, also it will affec the UX as most of the users now want to have the ability to search the Internet on their smartphones any time and anywhere.
30% of people would prefer to buy something via the internet on a tablet, and nearly that again would prefer mobiles. The age of desktop browsing has long been replaced by that of the mobile world, where 57% of people use their phones to regularly browse the internet. Yes, you should definitely have a responsive website. (Source Ofcom, UK)
For the future, 'E-commerce Hosting' as a title has nothing to do with responsive websites. Please choose your title more carefully.
More than 10 countries have a 50%+ searches happen using Mobile. so we should definitely focus on Mobile Friendly Design too. thats why all the major Seach Engines focus Mobile Friendly Results on their Search Results.