Mobile Wifi R219 Top-up nightmare!!!!!!

[RGPO1]

I've been using a Mobile Wifi R219 whilst working from home.
When it needed topping up I popped into the shop and was able to purchase 100G of data for £50 for 90 days on Pay as You Go - perfect. No problems at all.

When the data run out I tried to top up on line and then only option was 15G of data for £25 (again Pay As You Go) so I purchased one of these so I could start work that day as I had some important meetings. There was no option for the 100G data for £50.
I spoke to one of your customer service people who advised me to top up another £50 and they would be able to add the 100G of data - when I had done this I was informed that they couldn't do it and that I would need to wait until that data was running low and call back so that the 100G of data would be applied.
I called this morning and was asked 2 security questions - one about when the SIM was activated and when my last purchase was only to be told I had got one of the questions incorrect and that I would need to call another number to sort this out - the number they gave was incorrect and came back as being non-existent!!!!!! I felt the person was really, really unhelpful.
I then had to go online and purchase yet another top-up of £25 of another 15G of data! 
When I tried to register the SIM and number I'm unable to do so as it sends a text apparently and I'm not able to access that via the mobile hotspot device.
It has been nothing short of a nightmare if I'm being honest and I would love an answer on why I can't purchase 100G of data via your website by a normal top up (which I can do in your shops) and how I can use the £50 credit I have to actually get the 100G of data I originally wanted to purchase. 

[Evie]

Hey there @RGPO1 - The deals offered can vary on where you take it out and when you take it 👍 That being said, we do currently have a Big Value Bundle deal which is £50 for Unlimited Data, Calls and Texts 🤗

In regards to using the credit you added to your account, I would advise to contact us on social media so that we can see how to best use this credit towards a plan! Make sure to include a link to this forum thread, along with your mobile/account number to save you repeating yourself.

[RGPO1]

Hi @Evie many thanks for the reply.

I don't need a deal with a bundle including minutes and texts as I'm only using this for data for the Mobile Wifi.

I'll get in touch with the team as you suggested and hope that can provide some clarity so I can get this sorted rather than having to top up data once a week which is proving to be expensive.