Deneid pre-approval

Our Insurance company denied pre-approval for my blood test for Vitamin D and saying that it was not covered by our policy.

Since it is covered by the policy and benefit provided, they have to approve my blood test accordingly.

I went to the Hospital last week as I am having severe body pain and leg cramps. Hence the Doctor asked me to do the blood test for Vitamin D but the insurance company declined my blood test

Please look into the matter and get an approval from Insurance company so that I can do my blood test under insurance policy.

Are the sentences above grammatically correct? Please help me