This may or may not solve your issue (I'm assuming it won't fix the issue with outbound/inbound calls) but it may make accessing Facebook/news/other sites more consistent. I am not Vodafone technical support.
I've changed my DNS addresses to an alternative and it appears to be working. This needs to be done on individual devices in order for it to work. I don't recommend changing these settings on your broadband router, unless you are confident enough to do so.
Google DNS 220.127.116.11 18.104.22.168
Cloudflare DNS 22.214.171.124
These addresses may fix one of your isses at the very least. All the best.