Does Recovery of maintenance charge is legal and how can I close this legal notice.

I am 25 Year Old from Uttar Pradesh, working an automobile company. In last month i was searching for a part time job. In last week (16.10.2019) i found a call from NexGen Servicess they offer me for part time online DATA Entry job, after discussion with them i agree to work with them. after completing all process they provide me all details. the work was to start on 18.10.20.19. I had to go out of Station on the evening of 17.10.2019 for next 15 to 20 days for a sudden urgent work. for this, i informed them by Mail and text massage that i am unable to work there. But Did't reply.I have received a legal notice on the 24.10.2019 by Mail for recovery of maintenance charge of 55999. Them Notice is also attached :- Legal Notice For Due Recovery Ref. No P/44/QL7. Dated: [24/October/2019] REGD.A.D. LEGAL NOTICE. _________________________________________________________________________________________ To, [Client :- [NAME] Dear Sir, Pursuant To The Instructions From And On Behalf Of My Client NexGen Services, Through Its Legal Department, I Do Hereby Serve You With The Following Legal Notice: - 1. That My Client Is A Sole Proprietor Firm Under The Name And Style Of M/s NexGen Services. 2. That My Client Is Engaged In The Business Of Outsourcing Work Of The Data Entry Etc., 3. That Against Your Valid And Confirmed Order My Client Did Your Job Work From Time To Time On Credit Basis As You Have Running Credit Account In The Account Books Of My Client Operated In Due Course Of Business. 4. That In Spite Of Acknowledging The Liability Of Payment Of Principal Balance Of Rs. [4999]/- You Have Been Miserably Failed To Make Payment Of The Said Amount Due To My Client From You Deliberately With Malafide Intent, Hence You Are Liable To Pay The Said Principal Balance Amount Of Rs. [55999] 5. That Thus You Are Liable To Pay The Total Amount Of Rs. [55999]/- INR. To My Above Named Client And My Above Named Client Is Entitled To Recover The Same From You. 6- That My Client Requested You Several Times Through Telephonic Message And By Sending Personal Messenger To You For Release Of The Said Outstanding Payment, But You Have Always Been Dilly Delaying The Same On One Pretext Or The Other And So Far Have Not Paid Even A Single Penny Out Of The Said Outstanding Undisputed Amount. I, Therefore, Through This Notice Finally Call Upon You To Pay To My Client Rs. [55999]/- INR. To Be Continued. To My Client Either In cash Or By Demand Draft Or Cheque Which Ever Mode Suits You Better, Within Clear 15 Days From The Date Of Receipt Of This Notice, Failing Which My Client Has Given Me Clear Instructions To File Civil, Criminal., Suit For Recovery And Other Misc. Proceedings Against You In The Competent Court Of Law And In That Event You Shall Be Fully Responsible For The Same. A Copy Of This Notice Has Been Preserved In My Office For Record And Future Course Of Action. _________________________________________________________________________________________ RAJESH R