Try the following:
1. Do not set anything in the Signature nor Encryption tabs of the RP settings
2. In your ADFS server, export the "Token-signing" certificate and use that for the Verification certificate in "Setup > General > Authentication"
Then for the logout if you'd like to use that too:
0. open ADFS Managment
1. Click on Relying Party Trust
2. Select your WHD Relying Party Trust (in your case, ihelp)
3. Select Endpoint tab
4. Add new one
5. Select SAML Logout; POST; URL "https://<ADFS_Server_IP/domain_name>/adfs/ls/?wa=wsignout1.0" and Save changes.
Use the same logout URL in WHD.
The bit that you are missing is the issuance transform rule in ADFS on the RP trust as a claim rule, create one using AD as the source change SAM-Account-Name to NameID