Employment contract help

I have recently resigned from my Company A and they have requested that I pay out my RM8k bond. However, they are not actually my legal employer as they used an agent to assist with the process. As per my passport, I am actually employed by another company, Company B. Company A and B have a legal agreement whereby I provide my services as a consultant and in return company A pays a monthly consultancy fee. The RM8k bond clause was only included in the contract issued by company A. Other details include (1) Company A gave me a promotion managed 2 departments but was given a pay cut in January and wasn't issued a new Employment Contract (2) They failed to fulfil the clause regarding medical insurance. Therefore I was wondering, given that my legal employer is company B and reasons 1 2, is the contract I signed with Company A even legally enforceable ?

Appreciate all the help!