Unfair claims

I was admitted at sunward park hospital on the 10th Feb and got discharged on 14th Feb 2022. The claim was submitted to my medical aid which paid 18k n refused to pay the balance of 4K upon enquiry my husband found out that the reason the medical aid rejected the claim was because sunward park submitted an estimate of 22k so now we are left with a bill of 4K which we have to pay because of their incompetence. Will never recommend this hospital to any of my family members and friends