Can my company ask me to sign 1 year bond after joining, without mentioning in the offer letter?

I joined company-A, and while joining I knew that I will be working as a contractor in company-B. But there was no mention of 1 year bond in Company-A’s offer letter (no mention orally also). After joining, 2 weeks later - Company-A asked me to sign deputation letter, which mentioned 1 year bond (since I am being deputed to Company-B ). When asked about this, Company-A told it is a standard practice in the industry. It has been just 2 weeks of my joining. I do not want to sign this bond. I do not have any other offers also. What should I do now? Please share some valuable suggestions.