A true Income Protection Plan (IPP) is usually a very different beast to Payment Protection Insurance (PPI). Exterminator has replied as if you were missold a PPI policy, and if it is one of these then their comments are very valid. If it is an Income Protection Plan, then proving misselling is not as straightforward, as a number of the scenarios listed may not apply.
An Income Protection Plan is also frequently known as Permanent Health Insurance, and is not usually sold as an add on to a loan or credit agreement. Income Protection is designed to replace your income if you are unable to work due to illness or an accident, not just cover the repayments on a loan. Someone who is employed in gainful employment is, in many ways, precisely the type of person for whom Income Protection is designed, as the benefit level should be fixed with reference to your salary so that it covers not just mortgage and other loan payments, but your household bills and provide you with spending money on top. The deferred period on an Income Protection Plan is commonly longer than a PPI policy - 3 or 6 months is common - and is usually fixed to take into account any period that you will still be paid your full or a major part of your salary by your employer and could manage with savings. The period over which benefit could be paid is also much longer, typically up to age 60 or 65.
This is not to say that Income Protection Plans cannot be missold. You may have always been in an occupation with very generous sick pay provision such as longer serving public sector, or suffer from a medical condition that would normally preclude a valid claim - the vast majority of claims for Income Protection Plans are musculo-skeletal (e.g. bad backs) and stress.
It is important that any misselling claim you do submit is sent to the correct company, which should be the company that sold the policy, which in the case of Income Protection Plans is not often the provider of the policy as this has to be an insurance company.