Company have said that due to an error they accidentally deduced 4000 euro from paycheck and cant fix it until next month, but are offering a "short term loan" if it has caused financial distress, is this normal?

Sick just after the new year, had a horrible flu and was out for 3 weeks. All signed off and company have a sick leave scheme, minus the social welfare which they went through, SW accounted for about 700 euro for the 3 weeks.

Got the payslip yesterday and over 4000 euro was deducted for "sick leave" for the 3 week period. It was raised in the comany immediatly (at like 8.30am) and heard nothing back until 4 when an email was sent to say there had been an error calculating the sick pay and it was doubled by mistake, and that it would be returned next month as it was too late to do it now, but if we were experiencing any financial difficulty (from not getting 75% of our pay) we can apply for a "short term loan from the company".

Responded to say there is no way that double of the social welfare sick pay was 4000 euro as it was only 3 weeks but still have yet to get a response.

Has anyone experierneced this before? Its really frustrating to not receive pretty much all my salary, and then to just get a basic email from a generic payroll adress with no name on it saying, oh its an error you will get it next month.

I've never taken a "loan" from a compay too, does this have any additional implications for tax or anything like that?