Lost Housing Benefit and Council Tax Support despite witdrawing an application for Universal Credit.

The claimant who was receiving Housing Benefit and Council Tax Support lost these benefits because he applied for the Universal Credit, but he later withdrew his application for the Universal Credit (the UC was not awarded), yet the Council has not reinstated the benefits he was receiving, despite that withdrawal. So the claimant does not receive any benefits now, neither UC nor HB/CTS.

The claimant of the Housing Benefit and Council Tax Support was mislead by the Council in a decision of 3/3/18 reviewing the benefits (and awarding them), because the decision said that:

“I note that you are entitled to maximum entitlement and therefore may also be entitled to Income support/Income based Jobseeker's Allowance/Guarantee Credit. Should you wish to claim, please contact your local Department for Work and Pensions office. If you are awarded any of these benefits, please contact this office immediately. This will not affect your current award of Housing Benefit.”

Because of that the claimant first was filling in a form for Income Support, then the claimant found out that he should be completing the Employment and Support Allowance (ESA), then when filling in the ESA the claimant was advised that again it was an incorrect form and should apply for the Universal Credit.
There was no information in the aforementioned Council's decision about ESA or UC, and the decision clearly stated that "This will not affect your current award of Housing Benefit."

But when the claimant applied for UC the Council first suspended and soon after cancelled both benefits (HB and CT Reduction).

The claimant would not have applied for UC, if he knew that the current benefits would be cancelled, including Council Tax Support, but the Council misled the claimant in their decision as shown above.

The claimant due to ill health struggled with completing all the forms necessary for UC (some of which were over 50 pages long and required additional input on separate pages), and decided to withdraw his application to UC.

The claimant believes that the benefits he was receiving before (HB and CTS) should not have been cancelled by the Council when the claimant applied for UC, because applying for UC does not mean that the claimant would be awarded UC. Common sense says that the Council could cancel HB (but not CT Support, why did they cancel CTS at all?) only after UC would be awarded and not before. This is because a UC claimant before receiving an award of UC can withdraw his/her application, as it happened in this case, so the Council made a mistake by cancelling his award for the benefits, because these benefits are acquired rights, so they should not have been cancelled without a good reason, and should have been reinstated when the claimant asked to reinstate them (without a need to apply for them again), especially since the Council in their decision misled the claimant as shown above.

Is there any legislation or additional arguments, which the claimant may use to persuade the Council to reinstate the benefits they cancelled without any good grounds, like in this case? Are there any similar cases?