EI sick benefits and retroactive LTD payment

I never actually got LTD. I got a lump sum payment and they issued me a T4 with a retroactive payment as “group wage loss replacement plan”. They did the special breakdown form and applied about $3500 to the first year.

If I had got LTD it would have started end of August, but I was denied. I didn’t apply for EI sick benefits until November of that year. So I’m wondering if the $3500 would be counted as coverage for September-December at $875 a month so that I only have to pay back EI for November and December at $1750. Or do they just take the whole amount for the year that I received in LTD?

There were no specific dates identified in the settlement agreement, just lump sums per year. I’m thinking I should have filed my taxes to have the whole lump sum applied to 2019 only since my tax amount would be less than paying back all the EI.

As you can probably imagine, four years later and I’m still trying to figure out how to get out from under all the debt I incurred while waiting for this to be settled. Any advice is greatly appreciated!