RCM on freight reimbursement

I have cement business retail

I am owning a lorry which is loading cement from company and unloading at my shop

The said expenses of frieght through fuel and maintenance born by me only

But after paying theese company reimbursing the freight by calculating number of bags purchased × some what 10 per bag

Example - purchased 100 bags at 390

Fuel cost + others email to 10 per bag ,

Now cost per bag =400

I am selling it (thought its sold at cost price) for Rs 390(because 10 is reimbursement from company)

Question is

Am i liable to pay rcm on freight ??
OR
There is any liability to pay 18GST or 5%rcm for that reimbursement because they are paying me (assuming that it may be a supply ??)

Any opinion pls