Medicare for 2025 – impact of where selections are made

I am a retiree whose company uses ViaBenefits for the insurance options. So I have gone through them in the past to make my selections. They handle the registration of my options as well as the automatic payments from my bank account and the automatic reimbursement each month after the premiums are paid (the company provides a dollar amount each year for premiums, up to retiree to select their desired plans and pay any cost above the specified dollar amount).
My question – if I use Medicare.gov or Tom Dillion to update my selections for 2025, do you know if I can do that without jeopardizing my retiree benefit? My concern is that the company I retired from may not reimburse if I don’t continue to use ViaBenefits.
Thank you for all your information on these Medicare changes!