• My current company not issuing Relieving and experience letter

I was serving the last 10 days of notice period of 2 months and suddenly the HR people came up to me saying that i have found with some inappropriate communication with the clients i am working with. A complaint has been raised by the client, according to HR people.They suspended me without any proof and my relieving is on hold till the issue is resolved and they have not showed me any proof. The other company where i had to join are not accepting the delay as I told them to join as soon as I complete my notice period of 2 months. I am about to lose the job in the new company, what should I do?