A parameter cannot be found that matches parameter name 'Replace'

[Efff dd]

trying to create a mail contact , i get the error "A parameter cannot be found that matches parameter name 'Replace'" 

trying to populate an empty ad attribute

set-MailContact -identity $UserName -Replace @{onsitemailroutingaddress="$UserName@test.onmicrosoft.com"}

[#2]

the -Replace is not a parameter of Set-MailContact
it seems you are using the Replace from AD Module in Exchange Module, which is not applicable.
You can read more about it here
https://www.michev.info/Blog/Post/2011/bulk-replacing-proxy-addresses-based-on-a-pattern