Just a tip–that all of your specialists should send their reports/consultations to your family Doctor–so likely your family Doc. can send in all the updates.
If they are late with any other cheques then an email or fax (proof of receipt) should be sent explaining how their negligence in issuing your benefits is having a negative effect on your health and increasing your stress.
If you have any nsf fees or other losses due to the delay then the Insurer should reimburse you those amounts.
Just be to the point and polite.
Also my tip is when you send in all the requested information to your Insurer also request a complete and full copy of your claim file and related documents for your records.–Anytime they ask you for an update ask them too. If you feel bullied or targeted , trust your instincts , and get your records. They hate it but it is reasonable for you to have.