Then you will have to file for bankruptcy within a few months, merchants since the profession has existed as such have strove to accept as many currencies as possible in order to increase the number of people they can serve and the profits they can generate, and this is just as true today as it was back then, so by only accepting a specific altcoin for the purchase of your products you will severely limiting yourself to just the users of that coin, reducing your sales and making your business very unlikely to succeed.