Mailing Bags and Boxes

Hi

I am having more customers complaining that the mailing bags I use have been torn open by Royal Mail and the courier and items are missing.   This has only been happening over the last three months and I haven't changed my mailing bags.   One customer told me that the contents of her parcel were thrown over her side gate!!   I am researching prices etc for boxes and stronger mailing bags and wondered if anyone could recommend a company please.    Many thanks for your help.

Thank you.   I'll have a look.