Dsp Blackrock Mutual Fund — Unable to redeem money from my folio and no support getting from DSP customer care or from local office.

I have opened a SIP folio in the name of my son who is minor and my name and PAN is added as guardian in the folio. I am first holder of that saving bank account which is added in folio and from which monthly SIP contribution is being deducted.
Now When I am in crisis of money and wanted to redeem some amount from that folio, DSP MF is saying that as per SEBI guideline you have to open a saving bank account in the name of minor as first holder then change the account number in the folio and then you can be able to redeem money from this folio. I have followed the process, opened a saving bank account in the minor name and requested DSP MF to change account number in that folio so that I can redeem some amount from that folio to fulfil my crisis requirement. Here DSP MF is neither changing the saving bank account nor helping me out in any manner. Even they stopped responding to my calls. Please help me and guide, what should I do in this situation and how to redeem my own invested money