They are providing me with '220 Mbps of speed but I'm only getting 28mbps for the download and around 4 Mbps for the upload.
By itself, that doesn't really make much sense.
Firstly, what technology are you on: I am guessing it's FTTP, but I don't want to rule out G.Fast? And although it's almost certainly via an Openreach connection not an altnet, can you confirm that? And can you give the Unicom name of the service you have bought?
Secondly, how are you measuring the download and upload speed?
Thirdly, what sort of router and/or modem do you have connected to the line? Is it your own, or something that Unicom provided?
Clearly if you have a "220M" FTTP and are only getting 28-40M, something serious is wrong.
The two main possibilities I see are:
1. You have been provisioned on a 40/10 or 40/2 profile; or
2. There is something very seriously wrong with your home network or router.
If the profile is wrong, then regrading to 300M might fix it.
If your home network is borked, then it won't make any difference at all. But we can't help you with that one unless you describe what you have.