Yes. It is safe to use your card on myvishal.com. You have additional authentication for VISA cards- Verified by Visa (VBV) and Master cards - MasterCard Secure Code (MSC) offered by respective merchants.
It is unlikely that such a situation will arise. However, in the event that it does, please call our customer service desk or write a mail to customercare@vishalretail.co.in, MyVishal will address this at the earliest.