Falsified cheque bounce issue

My uncle has been running a micro finance company and one of my female Colleague invested totally 7 lakhs by means of cheque and cash. She gave 5 lakhs cheque in my name and she asked for a security cheque, during this time my uncle was short of cheques. So I offered my cheque for 5 lakhs only, this 5 lakh amount was settled by my uncle by means of cash and 1.5 lakh cheque from his account. But during this time my colleague went on maternity leave and I missed to collect the cheque I had given. Since one year my uncle has borne losses and he is not able to pay 2 lakh pending amount. Recently 10 days back my colleagues has presented the cheque I had given claiming I owe her 5 lakhs and sent me a initially notice from her lawyer. All this is bangalore and we both still work in same organisation. Before all this happened she also received 20k from me telling her on sms or watsapp tht it's 10% of my contribution bcos I can't pay her exposure. How do I go about defending this, appreciate any help. Even if it means I have to settle her 1.8 lakhs and get her off this nuisance.