A hot flash is a feeling of warmth spreading over the body that is often most strongly felt in the head and neck regions. Hot flashes may be accompanied by perspiration or flushing and usually last from 30 seconds to several minutes.
I have listed the hours along each method. In store. If you are in a Walmart store the customer service desk is open between 8am-10pm. The service desk is generally at the front of the store near the optical department. By phone. You can call 1-800-WALMART between 7am-6pm.
If you mean 24-hour, in-store, customer service (financial services, returns, etc.) the answer is no. The customer service desk closes at 10 pm and reopens at 8 am at 24-hour Walmart Supercenters and Neighborhood Markets. Usually the one at my store closes around 10 PM and opens back up at 7 am.