HDFC Bank Personal Loan — Illigal way of approving loan

Dear Sir/ Madam,
I am a existing personal loan holder of HDFC Bank. I had taken one topup priviously on my existing personal loan and the process done smoothly without any dispute. but when I applied for second topup after 9 months they came to me to collect the papers but up to the last moment they never discloused the amount they are giving me as a topup. whenever I asked about it they told me that it is not finalized yet..they signed all the agreements without disclosing the tenure and amount. Since i need money very badly i thought that everything will be fine and signed all papers.
Before this i told them that don't change my tenure which is 60 months. but they changed my tenure from 60 months to 48 months because of that my EMI increased by RS 1000/- per month. After that I told them that it is wrong tenure that you had given me but now they are not intertening in this matter. they had given me 19000 check as a topup amout which is not yet encashed still they are asking for the new EM.I. I requested that i am not able to pay this much amout please reshedule my loan tenure or cancell it if it is not possible. they promissed me to do the needfull. but not doing anything. their recovery agents calling me again and again and harassing me.