There's this company I resigned earlier this month...

We would like to inform you that according to the Qatari Labor Law if the limited contract is finished then below article states:
Article 21
The employer, the Competent Authorities, and the Ministry of Labor and Social Affairs may agree to transfer the Foreign National laborer to another employer before the time limit in the contract has been reached or after five years of working for the employer if the contract did not specify a time period.
The Foreign National laborer may, with authorization from the Competent Authorities and the Ministry of Labor and Social Affairs, transfer to another employer in the event of the Recruiter’s death or dissolution of the body corporate for any reason.
In all cases, the employer serving as the Recruiter shall not have his legal rights, or the contract between him and Foreign National, violated, in accordance with the referenced Labor Law.
The aforementioned article organized the cases of which the employee can transfer to another company as follow:
• With an approval from the employer (Whatever the contract type is)
• After completing five years on unfixed term contract
• The end of the fixed term contract
• The death of the employer
Therefore, if the sponsor asked for money to transfer the sponsorship then that is legal violation and you can file a complaint in the Ministry of Labor and explain the details to cancel the visa to be able to change the work.
For the end of services the below article states:
Article (15):
The employer shall, in addition to any amounts due to the user at the end of his service, provide a termination indemnity benefit to the employee who has spent more than one year or more from the date of this law. For each year of service, and the user is entitled to the bonus for fractions of the year by the amount of time spent in service.
The employer shall be entitled to deduct from the remuneration the amounts to which the user is liable