Accountant closed ltd company before VAT return

Hi, looking for some advice here because I've exhausted all other avenues. Basically, I contacted an accountant and he recommended I operate as a sole trader rather than a ltd company. I had asked him to get back the £2700 I'd paid so far in corporation tax and said I'd be fine to switch to sole trader if that's what he recommended. However, he closed the company before I got my refund and my £2700 has gone to the Crown, and I got another £2700 bill for self assessment.

I've had to set up a payment plan with HMRC to pay my self assessment, which is costing me £383 a month, plus a £1000 deposit I paid upfront to keep it under £400 a month. This is the equivalent of my half of the mortgage and I need to keep paying this until September.

The accountant has now asked for another £600 fee to reinstate the company and claim the refund again, but this will cost me approx £700 in fees. So essentially it will cost me £1300 to get back £2700, and £600 is to pay the accountant who got me in this mess in the first place. It's been really stressful, I've had to go to the bank to ask for help aligning all my outgoings because I have very little room for error.

The accountant said he "gave HMRC plenty of time to respond" before closing the company, which he clearly did not 🥹

Any guidance much appreciated, also want to know if the accountant has been negligent. Many thanks