Oh dear, that's very annoying. Did you test indoors or outdoors? If you have tested indoors, I advise you to turn on 4G over WiFi. This will give you better range and your speed will also be better (due to the fact that the range inside is less good than outside, thick walls, etc.).
If you have poor coverage outside, you can check this by going to Network check on the Vodafone website. There you can also indicate when the complaint will persist for longer. Vodafone will then look into this with you and will come back with an answer.
Is the network not working as it should for more than 45 days? Do the Vodafone Network check and we will help you further. In the event of a disruption of more than 12 hours at your home or business address, you may be entitled to compensation for the inconvenience. Then request compensation.
I use Google translate!