Provision entry as of March

Excess provisions are not encouraged and telephone expense are recorded when they incur. However, to clarify your doubt, provisions are created as a result of past events when economic benefit outflow is probable. Here, there is no past obligation and hence, provision cannot be created for next month expenses. Plus no need to create provisions for future operating expenses as they are classified as normal activities. There is no double entry that you can recognise a provision for as the event did not occur. 

Telephone bill a/c -> (this event did not occur to recognise it on income statement as it will reduce profits)

CGST

SGST

To Provisions a/c

hence this double entry is invalid and you can create a reserve fo telephone bill out of retained earnings if you like.