I’m sorry to hear about the experience you are having @MaryP.
It’s very disappointing to hear that your LA are saying they need to review your support package/plan so that you can use it to pay an agency rather than a PA. This sounds overly prescriptive and inflexible, especially if they do not have the resources to carry out the review in a timely manner. As you say, as long as the outcomes are still being met, you should be able to use your budget to purchase the support as you decide. There is info on this in the SDS Handbook here: What happens if you do not spend all your support budget? - The SDS HandbookThe SDS Handbook
Different LAs take very different approaches to recovering surplus funds and it sounds like yours is stricter than some (certainly where I live and work). This should be clearly stated in your direct payment agreement. From what I know of different LAs, most will still leave you with a balance of around 4-8 weeks. There is a recent feed on this here: Where, if anywhere, is the authority for reclaiming surplus funds? - Legislation & Guidance - SDS Forum (sdsscotland.org.uk)
Sadly, you will probably have the best chance of achieving a positive outcome by making a complaint using the LAs social work complaints procedure (and/or via a local councillor/MSP/MP). As always, I would advise you to contact your local independent SDS support organisation or community brokerage service, who may be able to negotiate with the LA on your behalf (if required): Find Local Information and Support - Self Directed Support Scotland | Self Directed Support Scotland (sdsscotland.org.uk)
Best of luck getting the support you need back in place for you and your child.
Justin