Review Unprofessional people

These guys were engaged for providing GBP license service by the parent company before spin off. For that they took advance from one company and there was a spin off of an entity and the they did not have any engagement / mandate with the new carved out entity. They had invoiced a lot of invoice without rendering any service in the name of accounting fee, admin fee etc.,
The new carved out entity mentioned that they did not engage International Proximity (IP) any mandate for any of the services. Also, advised that the statutory audit will be managed by in house team and do not need any support from IP as there was zero operation and no transaction. Intially IP agreed to these and about USD56K they agreed to treat as advance received. One of the senior members of the team agreed to this on email.
Later, they are having a call and refusing to treat this receipt as advance and were threatening that they will create a lot of problem by dealing with the government officers. Highly unprofessional. Do not recommend them.