Is it permissible, in Sharia, to impose a financial fine on tenants for not renewing their contracts with a property management company that was later agreed upon by the landlord, and why was a higher rent imposed on them?

The tenant has the right to complete the term of his contract under the same conditions. The landlord has the right not to renew the contract after its term expires, or to raise the rent as he deems fit, even if it exceeds the rent of others. In this case, there is no objection to the company raising the rent. The amount called "fine" is considered part of the new rent, and it is an expedited portion of it that is will be deducted from the monthly rent.