Extra Marks Learning App - Extramarks package taken for Class XI and XII

I had purchased subscription for *yrs for class XI and XII for my son Anmol Gupta on ** Dec **** which was starting from April **** onwards vide Order No ********, Invoice Number UP/R/****/******, Invoice Date: **.**.**** which includes class X package (for the year ****-**) as complimentary.
After activation of package taken for class XI in April ****, my son is facing problems to use it. Tried many times since Jan ****, but failed to contact to your executives, Sh. Ashutosh Verma and Sh. Nikhil Goswami (sales executives), who was dealing your Dehradun Office, left Dehradun.
I also tried many times on mentor no as they provide me, but failed. Then contact to Customer care, they asked to provide email but once again no response from your side. At last, in end of June ****, the Customer care executive told me to raise the issue through mail.
Now, I am not interested to keep going with this package because I am fed-up with your services from Jan to June ****. So it is requested to cancel this package and return my money as soon as possible.