How does one know that the DP has updated the account after each transaction?
The DP gives a transaction statement/holding statement periodically, which will contain details of current balances and various transactions made through the depository account. DP may provide the transaction statement at intervals shorter than the stipulated ones at a cost.

At what frequency will the investor receive his Transaction Statement from his DP?
DPs have to provide transaction statements to their clients once in a month, if there are transactions and once in a quarter, if there are no transactions. Moreover, DPs can provide transaction statement in electronic form under digital signature subject to their entering into a legally enforceable arrangement with the Beneficiary owners (BOs) to this effect.

What is to be done if there are any discrepancies in transaction statement?
In case of any discrepancy in the transaction statement, one can contact his/her DP. If the discrepancy cannot be resolved at the DP level, the aggrieved investor should approach the Depository (NSDL or CDSL).

Who should one contact in case of any investor complaint / problem / query?
In case of any investor complaint / problem / query one may first contact his DP. If DP is unable to solve the complaint / problem / query one should approach concerned depository. i.e NSDL and CDSL. If one is not satisfied, one may approach SEBI. One may also approach SEBI directly.