Well, first of all (in reply to your comment) there definitely is such a thing as "Indian English" - even if Microsoft don't know about it! :)
Take a look at Wikipedia: Indian English to start with.
In this article from the British Library, we can see that one way in which Indian English differs from British English is the way in which it handles the definite article:
Feature: zero article
Explanation: the indefinite article, a or an, or the definite article, the, are often omitted
Example: and then, uh, there was, uh, no fear of going to an Indian restaurants and sending your suit for a dry-cleaning _ next day, because they were well-ventilated etcetera and I’m, I’m very pleased that Indian food has come _ long way
Those underscore '_' marks show where the article ('the' or 'a') has been omitted, in the example spoken sentence. The website has an audio recording of a native speaker saying that sentence.
So although "We will hold the slot for the next 5 minutes" would be normal usage in written British English, "We will hold the slot for next 5 minutes" could well be more usual in Indian English. The choice may come down to what kind of impression you want to give your customers - you'd be more familiar than me with the social ramifications of using a more British/American style of English as opposed to a more Indian style, I'm sure.